Experimented with moving RVM interpreter cases to separate methods.

Conclusion: this is do-able and useful when compiling to JVM but also
costs 20-25% performance (for only the call instructions).

Postponed until we start working on JVM translation.
Implemented field projection for rel, lrel and map.
Merge branch 'master' of https://github.com/cwi-swat/rascal.git