Major reorganization and bug fixes

Various major overhauls have done:

- The compiler now caches the intermediate .mu files and consults them
to find imports (before the Rascal source was parsed for this).

- To achieve this (and to overcome limitations of readTextValueFile with
respect to overloading) all constructors of muRascal have been made
unique. This has resulted in hundreds of renaming in many places.

- The cyclic breaking and crash recovery of the compiler have been
improved.

Bug fixes:

- overloading resolution
Added a view and statistics tool for RVM files

view:
- lists the details contents of an RVM file
- has options to show the instructions of specific functions.

statistics:
- collects statistics for all RVM files in (nested) directories.
Intermediate commit to get a built version to experiment at level 1.
Merge branch 'master' of https://github.com/cwi-swat/rascal.git