Use the same mechanism for freeing IVars and arrays now that we have the
infrastructure in place.
Retire the typedefgenerator plugin.
Merge pull request #45 from pjonsson/retire-tdefgen

Retire the typedefgenerator plugin.
Merge pull request #44 from pjonsson/free-ivars

Conflicts:
	lib/Feldspar/Compiler/Imperative/FromCore/Interpretation.hs