Simplified the getting of a function type now that the more complex (native) type is no longer used for abstract impls.

Signed-off-by: Dimitar Dobrev <dpldobrev@yahoo.com>

Conflicts:
	src/AST/Method.cs
Merge pull request #278 from ddobrev/master

Simplified the getting of a function type now that the more complex (native) type is no longer used for abstract impls