[FALCON] MXML protected vars as attributes

[Alex Harui]

@Gordon (mostly):

I ran into a situation where someone is setting protected variables via
MXML attributes.  Is this "allowed"?  I thought MXML attributes were only
for public properties.  MXMLC lets this happen.  Falcon does in one case,
but not another.  What should Falcon do?

MXMLC and Falcon allows:

---Base.mxml---
<s:Group>
  <fx:Script>
     protected var foo:int;
  </fx:Script>
</s:Group>

---Actual.mxml---
<Base foo="1" />


MXMLC allows, but Falcon doesn't like:

---Actual.mxml---
<s:Group foo="1">
  <fx:Script>
    protected var foo:int;
  </fx:Script>
</s:Group>

IOW, Falcon is ok with seeing protected vars on the base class but not new
protected vars on the actual class.

Thanks,
-Alex