Implement Go To Source
Basic infrastructure is in place, I'll add identifier highlighting soon, but the body of the functionality is not yet
started as the compiler still doesn't provide correct AST positions...
review Apr/7 - Missing elements in AST. Even worse than Go To Declaration. Re-scheduled for M3
Go To Source fully works inside a single source file now.
Go to Source should work across source files now, and even into java sources as long at the platform is set up correctly
and few bugs are fixed in the right branch of javafxc.
Then the only broken thing would be go-to .java file inside the same project then.