Misc fixes and cleanups
Merge branch 'nat' of github.com:mozilla/shumway into nat
Fix interpretation of errorsAvm1 setting in generateActionCalls

Currently, the error handling wrapper is installed if the flag is set to `false`, where it should be the other way around.
Implement AVM1 globals `escape` and `unescape`
Use different index variable for inner loop in FrameDelta#_applyCommands
Fix AS2MovieClip's _insertChildAtDepth to make createEmptyMovieClip work
Don't try to send a complete message if an XHR request failed
Replace all uses of try/finally, because JS engines really do not like that
Merge pull request #1406 from tschneidereit/nat

Various fixes, mostly AVM1-related
Remove debugger statement
Merge branch 'nat' of github.com:mozilla/shumway into nat
Merge pull request #1407 from mbebenita/nat

Implements GL clipping with stencil buffers.
Small reference counting optimizations
Merge branch 'nat' of github.com:mozilla/shumway into nat
Make sure to begin paths when building clip rects.
Lazify FrameDelta initialization

Most frames will only be shown way after they've been initially created, so we can just delay the calculations required for initializing them until that time. That also reduces memory usage quite substantially for SWFs with long timelines.
Change the SWF parser's readBinary function to copy bytes instead of returning subarrays

At least for all usages that don't further process the bytes but just pass them on to the script thread. Otherwise, they just keep the entire SWF parsing buffer alive, potentially multiple times. Reduces memory usage by up to 40% (i.e., a certain specific case I measured goes from 263MB to 152MB.)
Merge pull request #1411 from tschneidereit/nat

Memory optimizations/ leak fixes
Show multiple backends side by side in the inspector.
Merge branch 'nat' of https://github.com/mozilla/shumway into nat