allow @:arrayAccess on abstracts if the underlying type supports it (applies to Vector)

git-svn-id: http://haxe.googlecode.com/svn/trunk@5941 f16182fa-f095-11de-8f43-4547254af6c6
deactivate abstract type parameter test that crashes Cpp compilation

git-svn-id: http://haxe.googlecode.com/svn/trunk@5942 f16182fa-f095-11de-8f43-4547254af6c6