Fix unit tests

[justinbastress]

On Windows, go test -v results in the following:

=== RUN   TestPositional
--- PASS: TestPositional (0.00s)
=== RUN   TestPositionalRequired
--- PASS: TestPositionalRequired (0.00s)
=== RUN   TestPositionalRequiredRest1Fail
--- PASS: TestPositionalRequiredRest1Fail (0.00s)
=== RUN   TestPositionalRequiredRest1Pass
--- PASS: TestPositionalRequiredRest1Pass (0.00s)
=== RUN   TestPositionalRequiredRest2Fail
--- PASS: TestPositionalRequiredRest2Fail (0.00s)
=== RUN   TestPositionalRequiredRest2Pass
--- PASS: TestPositionalRequiredRest2Pass (0.00s)
=== RUN   TestPositionalRequiredRestRangeFail
--- PASS: TestPositionalRequiredRestRangeFail (0.00s)
=== RUN   TestPositionalRequiredRestRangeEmptyFail
--- PASS: TestPositionalRequiredRestRangeEmptyFail (0.00s)
=== RUN   TestCommandInline
--- PASS: TestCommandInline (0.00s)
=== RUN   TestCommandInlineMulti
--- PASS: TestCommandInlineMulti (0.00s)
=== RUN   TestCommandFlagOrder1
--- PASS: TestCommandFlagOrder1 (0.00s)
=== RUN   TestCommandFlagOrder2
--- PASS: TestCommandFlagOrder2 (0.00s)
=== RUN   TestCommandFlagOrderSub
--- PASS: TestCommandFlagOrderSub (0.00s)
=== RUN   TestCommandFlagOverride1
--- PASS: TestCommandFlagOverride1 (0.00s)
=== RUN   TestCommandFlagOverride2
--- PASS: TestCommandFlagOverride2 (0.00s)
=== RUN   TestCommandFlagOverrideSub
--- PASS: TestCommandFlagOverrideSub (0.00s)
=== RUN   TestCommandFlagOverrideSub2
--- PASS: TestCommandFlagOverrideSub2 (0.00s)
=== RUN   TestCommandEstimate
--- PASS: TestCommandEstimate (0.00s)
=== RUN   TestCommandEstimate2
--- PASS: TestCommandEstimate2 (0.00s)
=== RUN   TestCommandValidate
--- PASS: TestCommandValidate (0.00s)
=== RUN   TestCommandClosest
--- PASS: TestCommandClosest (0.00s)
=== RUN   TestCommandAdd
--- PASS: TestCommandAdd (0.00s)
=== RUN   TestCommandNestedInline
--- PASS: TestCommandNestedInline (0.00s)
=== RUN   TestRequiredOnCommand
--- PASS: TestRequiredOnCommand (0.00s)
=== RUN   TestRequiredAllOnCommand
--- PASS: TestRequiredAllOnCommand (0.00s)
=== RUN   TestDefaultOnCommand
--- PASS: TestDefaultOnCommand (0.00s)
=== RUN   TestAfterNonCommand
--- PASS: TestAfterNonCommand (0.00s)
=== RUN   TestSubcommandsOptional
--- PASS: TestSubcommandsOptional (0.00s)
=== RUN   TestSubcommandsOptionalAfterNonCommand
--- PASS: TestSubcommandsOptionalAfterNonCommand (0.00s)
=== RUN   TestCommandAlias
--- PASS: TestCommandAlias (0.00s)
=== RUN   TestSubCommandFindOptionByLongFlag
--- PASS: TestSubCommandFindOptionByLongFlag (0.00s)
=== RUN   TestSubCommandFindOptionByShortFlag
--- PASS: TestSubCommandFindOptionByShortFlag (0.00s)
=== RUN   TestCompletion
--- FAIL: TestCompletion (0.00s)
	completion_test.go:262: Args: []string{"-"}, false
		  Expected: []string{"--debug", "--required", "--verbose", "--version", "-i"}
		  Got:     []string{"/debug", "/i", "/required", "/verbose", "/version"}
	completion_test.go:262: Args: []string{"--"}, false
		  Expected: []string{"--debug", "--required", "--verbose", "--version"}
		  Got:     []string{"/debug", "/required", "/verbose", "/version"}
	completion_test.go:262: Args: []string{"--ver"}, false
		  Expected: []string{"--verbose", "--version"}
		  Got:     []string{"/verbose", "/version"}
=== RUN   TestParserCompletion
--- FAIL: TestParserCompletion (0.00s)
	completion_test.go:310: Expected: []string{"--debug", "--required", "--verbose", "--version", "-i"}
		Got: []string{"/debug", "/i", "/required", "/verbose", "/version"}
	completion_test.go:310: Expected: []string{"--debug", "--required", "--verbose", "--version"}
		Got: []string{"/debug", "/required", "/verbose", "/version"}
	completion_test.go:310: Expected: []string{"--debug     # Enable debug", "--required  # This is required", "--verbose   # Verbose messages", "--version   # Show version"}
		Got: []string{"/debug     # Enable debug", "/required  # This is required", "/verbose   # Verbose messages", "/version   # Show version"}
	completion_test.go:310: Expected: []string{"--verbose", "--version"}
		Got: []string{"/verbose", "/version"}
=== RUN   TestConvertToString
--- PASS: TestConvertToString (0.00s)
=== RUN   TestConvertToStringInvalidIntBase
--- PASS: TestConvertToStringInvalidIntBase (0.00s)
=== RUN   TestConvertToStringInvalidUintBase
--- PASS: TestConvertToStringInvalidUintBase (0.00s)
=== RUN   TestGroupInline
--- PASS: TestGroupInline (0.00s)
=== RUN   TestGroupAdd
--- PASS: TestGroupAdd (0.00s)
=== RUN   TestGroupNestedInline
--- PASS: TestGroupNestedInline (0.00s)
=== RUN   TestGroupNestedInlineNamespace
--- PASS: TestGroupNestedInlineNamespace (0.00s)
=== RUN   TestDuplicateShortFlags
--- PASS: TestDuplicateShortFlags (0.00s)
=== RUN   TestDuplicateLongFlags
--- PASS: TestDuplicateLongFlags (0.00s)
=== RUN   TestFindOptionByLongFlag
--- PASS: TestFindOptionByLongFlag (0.00s)
=== RUN   TestFindOptionByShortFlag
--- PASS: TestFindOptionByShortFlag (0.00s)
=== RUN   TestFindOptionByLongFlagInSubGroup
--- PASS: TestFindOptionByLongFlagInSubGroup (0.00s)
=== RUN   TestFindOptionByShortFlagInSubGroup
--- PASS: TestFindOptionByShortFlagInSubGroup (0.00s)
=== RUN   TestHelp
--- PASS: TestHelp (0.00s)
=== RUN   TestMan
--- PASS: TestMan (0.00s)
=== RUN   TestHelpCommand
--- PASS: TestHelpCommand (0.00s)
=== RUN   TestHelpDefaults
--- PASS: TestHelpDefaults (0.00s)
=== RUN   TestHelpRestArgs
--- PASS: TestHelpRestArgs (0.00s)
=== RUN   TestWrapText
--- PASS: TestWrapText (0.00s)
=== RUN   TestWrapParagraph
--- PASS: TestWrapParagraph (0.00s)
=== RUN   TestHelpDefaultMask
--- PASS: TestHelpDefaultMask (0.00s)
=== RUN   TestWriteIni
--- PASS: TestWriteIni (0.00s)
=== RUN   TestReadIni_flagEquivalent
--- FAIL: TestReadIni_flagEquivalent (0.00s)
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
	panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xc0000005 code=0x0 addr=0x0 pc=0x558ccc]

goroutine 108 [running]:
testing.tRunner.func1(0xc042232d20)
	C:/Go/src/testing/testing.go:711 +0x2d9
panic(0x5c2040, 0x6f3da0)
	C:/Go/src/runtime/panic.go:491 +0x291
github.com/zmap/zflags.(*IniParser).parse(0xc04202bec8, 0xc0422d5c40, 0x0, 0x0, 0xc0422d5c40, 0x0, 0x0, 0x5d8800, 0xc0422e3101, 0xc0422d5c20)
	C:/Users/localadmin/go/src/github.com/zmap/zflags/ini.go:603 +0xabc
github.com/zmap/zflags.(*IniParser).Parse(0xc04202bec8, 0x6e4920, 0xc0422d5c20, 0x5fed1f, 0x17, 0x5a3080, 0xc0422c4f28, 0xc0422e3290, 0x0, 0x0, ...)
	C:/Users/localadmin/go/src/github.com/zmap/zflags/ini.go:142 +0xd8
github.com/zmap/zflags.TestReadIni_flagEquivalent.func1(0x607a33, 0x9b, 0x6ab0b8, 0xf, 0x6e0f15)
	C:/Users/localadmin/go/src/github.com/zmap/zflags/ini_test.go:325 +0x21f
github.com/zmap/zflags.TestReadIni_flagEquivalent(0xc042232d20)
	C:/Users/localadmin/go/src/github.com/zmap/zflags/ini_test.go:337 +0x93
testing.tRunner(0xc042232d20, 0x60a8b0)
	C:/Go/src/testing/testing.go:746 +0xd7
created by testing.(*T).Run
	C:/Go/src/testing/testing.go:789 +0x2e5
exit status 2
FAIL	github.com/zmap/zflags	0.087s

The former is presumably Windows-specific, but the latter seems to be universal.

[zakird]

Note: we should also add travis to the repo as well to prevent this in the future.