Reduce duplication in RppVmsMojo

[pengyuejiang]

emop/emop-maven-plugin/src/main/java/edu/cornell/RppVmsMojo.java

Line 44 in f49935b

// copied from VMS - is there a better way to do this?

In the comment above, many fields are copied from VMS. Think of a better way to address this problem. One potential solution could be to let RPS, VMS and RPP Mojos extend some interface Mojo that contains all the necessary fields, but may require a lot of redesign.