top down inference for comprehensions

git-svn-id: http://haxe.googlecode.com/svn/trunk@6104 f16182fa-f095-11de-8f43-4547254af6c6
bugfix : should return an iterator

git-svn-id: http://haxe.googlecode.com/svn/trunk@6105 f16182fa-f095-11de-8f43-4547254af6c6
fixed subtyping printing

git-svn-id: http://haxe.googlecode.com/svn/trunk@6106 f16182fa-f095-11de-8f43-4547254af6c6
added missing @:coreApi

git-svn-id: http://haxe.googlecode.com/svn/trunk@6107 f16182fa-f095-11de-8f43-4547254af6c6
Merge branch 'haxe/master'