Implement V8 stack trace style

[gbrail]

For compatibility with V8, we'll add a stack trace style that works the way that V8's stack trace format works, for instance as follows:

at repl:1:1
at REPLServer.self.eval (repl.js:110:21)
at repl.js:249:20
at REPLServer.self.eval (repl.js:122:7)
at Interface.<anonymous> (repl.js:239:12)
at Interface.EventEmitter.emit (events.js:95:17)
at Interface._onLine (readline.js:202:10)
at Interface._line (readline.js:531:8)
at Interface._ttyWrite (readline.js:760:14)
at ReadStream.onkeypress (readline.js:99:10)

In other words, each line has the format:

at (::)

or, for anonymous functions:

at ::

Since we now have three stack trace styles, we will add the following functions:

RhinoException.setStackStyle(StackStyle style);
RhinoException.getStackStyle();

These use an object of type StackStyle, which is an enum-style object with three possible values:

StackStyle.RHINO -- the default
StackStyle.MOZILLA -- Mozilla style
StackStyle.V8 -- the new V8 style.

Finally, "RhinoException.setMozillaStackStyle(true)" will now call "setStackStyle" to set the Mozilla style.