Merge pull request #914 from tschneidereit/master

Implement AS2 TextField.variable accessor
Merge pull request #916 from tschneidereit/master

Implement AS2's TextFormat#getTextExtent
Merge pull request #918 from tschneidereit/master

Correctly handle drawing groups within an embedded shape
Stub out classes required to get MIT Scratch SWFs running to the main interface