MXML features / fixes:
* Ant support
* fix: also find *.mxml on *-imports (incl. top-level and same-package)
* event listeners use joo.addEventListener()
* any AS3 code in <fx:Script> (we *do* support imports
  in the class body, so <fx:Script> code goes into the class
  body and <fx:Metadata> code goes before the class)

Still on the roadmap:
* support [DefaultProperty] annotation
* binding expressions (curly brackets) and <fx:Binding>
fix: really set fully qualified super class name in ClassModel
fix test now that fully-qualified superclass name is resolved
fix: also look for [Event] annotations in super classes