prevent recursive constraints (fixed issue #1337)

git-svn-id: http://haxe.googlecode.com/svn/trunk@6015 f16182fa-f095-11de-8f43-4547254af6c6
allow operator overloading on abstracts with @:op syntax (this may be subject to change)

git-svn-id: http://haxe.googlecode.com/svn/trunk@6016 f16182fa-f095-11de-8f43-4547254af6c6