Merge pull request #1308 from tschneidereit/nat

Add rough but working unit testing script for the SpiderMonkey shell
Avoid using closures in Object and Number as to speed up startup time.
Coerce as string before resolving names.
Merge branch 'nat' of https://github.com/mozilla/shumway into nat
Implement mouseX/Y.
Make sure the Mouse class is initialized before using it.
Use seperate flags for invalid bounds and rect.
Clone events when redispatched
Implement LoaderInfo::content
Ignore security checks in stage.
Write remoting ids in renderables.
Fix race condition when using Loader at high frame rate
Implement FontSymbol
Fix SoundSymbol stub
Load font symbols
Add BinarySymbol stub
Add assertions to check for unknown symbol types
Send graphics assets separately.
Merge branch 'nat' of https://github.com/mozilla/shumway into nat
Clean up some options.