use applied types in using completion (fixed issue #1403)

git-svn-id: http://haxe.googlecode.com/svn/trunk@5914 f16182fa-f095-11de-8f43-4547254af6c6
store cast fields in a_to and a_from

git-svn-id: http://haxe.googlecode.com/svn/trunk@5915 f16182fa-f095-11de-8f43-4547254af6c6