Fixed some compilation errors with respect to the new pdb types.
Working on compilation errors.
refactored the type hierarchy for Rascal-specific types.
reimplemented type reachability using a visitor instead of if-then-else.
added new abstract classes for Rascal types
More compilation errors fixed.
More compilation errors fixed.
better design for RascalTypeVisitor
Merge branch 'refactor-subtype' of git@github.com:cwi-swat/rascal.git into refactor-subtype
More compilation errors fixed.
Merge branch 'refactor-subtype' of https://github.com/cwi-swat/rascal.git into refactor-subtype
fixed compilation issues
Small fix in the NonTerminalType.
Small fix in the ResultFactory.
Merge branch 'refactor-subtype' of git@github.com:cwi-swat/rascal.git
into refactor-subtype

Conflicts:
	src/org/rascalmpl/library/util/Eval.java
Fixed one more compilation error and made a temporary fix of
NonTerminalType.
Running tests, fixing bugs: fix in the ResultFactory related to list
relations.
Merge branches 'master' and 'refactor-subtype' of https://github.com/cwi-swat/rascal into refactor-subtype
Small fix after merge with master.
Small fix in the FunctionType, and all the rascal tests succeed now!
Small fix related to the replacement of the writer with listWriter.