Lots more E4X implementation
merge upstream/master
Implement toAttributeName(); Remove dead code
fix crash in XML.setProperty()
Merge pull request #282 from tobeytailor/master

Delete accidentally commited files.
Fixes showURL menu and hides label for small screens
Fixes building examples for web
cleanup
Merge pull request #283 from artcompiler/e4x

More E4X
XML: remove _ prefixes on property names; fix enumeration; add test for youtube usage
Merge pull request #284 from artcompiler/e4x

XML: remove _ prefixes on property names; fix enumeration; add test for ...
Adjusts failconfig.txt for AVM2 tests
Speed up construction of large sprite symbols.