refactoring:
- It includes JDKDescriptors that define where DrJava should look for
certain JDKs.
- There is support for Mint, Nextgen (not complete) and Habanero Java
(not complete).
- The compilers determine what file types are supported and what
keywords should be syntax-highlighted.
This refactoring makes it a lot easier to add future research
compilers or JDKs.