Steps towards maintaining source locations in generated code.

Warning: some tests (related to data constructors with keyword
parameters) fail.

The basic approach is to associate location information with a small set
of strategically selected RVM instructions:

CALLPRIM
OCALL
OCALLDYN

In addition, Frames are extended with a location field (src) and that is
updated at run time for the above instructions.

MuPrimitives are extended with a new argument: List<Frame> stacktrace.
This gives access to the call stack and enables -- in combination with
the src field in each Frame -- production of very precise stack traces.
Merge branch 'master' of https://github.com/cwi-swat/rascal.git