improve error message when TFun unification fails

git-svn-id: http://haxe.googlecode.com/svn/trunk@6683 f16182fa-f095-11de-8f43-4547254af6c6
[As3] fixed Reflect.getEnumValue

git-svn-id: http://haxe.googlecode.com/svn/trunk@6684 f16182fa-f095-11de-8f43-4547254af6c6