Fixes in regexp implementation
Merge branch 'master' of https://github.com/cwi-swat/rascal.git
Merge branch 'master' of https://github.com/cwi-swat/rascal.git
Merge branch 'master' of https://github.com/cwi-swat/rascal.git
Module variables/modular execution/modular testing

Three interrelated problems are being addressed.

(1) Module variables where implemented in a way that was ill-suited for
incremental compilation. They are now handled in a later stage by the
Executor. Previously, we allocating a stack frame per module and placed
module variables there; problem: how to assign positions across modules?
The new solution is to place *all* module variables in a single table
that is created just before execution and is used by LOADVAR and
STOREVAR.

(2) All modules now have their own init function. Before execution of a
module all the init functions of the imported modules are called.

(3) All modules now have their own testsuite function. These are called
in sequence when testsuite=true in the Execute call. This enables
testsuite execution per module as suggested by Oscar.
Merge branch 'master' of https://github.com/cwi-swat/rascal.git