Added subtype declarations to TypeMap, removed SubtypeMap.

Added subtype declarations to TypeMap, removed SubtypeMap.

Merge branch 'cλash' of http://git.stderr.nl/matthijs/projects/master-project

* 'cλash' of http://git.stderr.nl/matthijs/projects/master-project: (32 commits)
  Support application of dataconstructors.
  Make mkAssign support assigning to a VHDLName as well.
  Split off record field selection AST construction.
  Only try to generate builtin functions for global binders.
  Never try to normalize global binders.
  Split off assignment generating code.
  Support single-alt selector case expressions.
  Add pprString convenience method.
  Support single-constructor algebraic types.
  Move type registration out of construct_vhdl_ty.
  Split off the VHDL type generating code.
  Actually use the introduced let from a few commits back...
  Error out when normalizing polymorphic functions.
  Add an empty let before starting normalization.
  Add and use a mkFunction utility function.
  Make beta reduction of Case expressions work for type arguments.
  Add function propagation transform.
  Improve debug output timing.
  Don't propagate types with free tyvars.
  Add is_applicable predicate.
  ...

Conflicts:
	VHDL.hs