Make IAdvancable instances add themselves to DisplayObject._advancableInstances instead of doing it in the DisplayObject initializer

That way, we don't have to do shape-testing in the base initializer.
Merge pull request #1469 from tschneidereit/nat

Make IAdvancable instances add themselves to DisplayObject._advancableInstances instead of doing it in the DisplayObject initializer
Fix font size calculation for static text
Merge pull request #1470 from mbebenita/nat

Check for zero or negative width/height arguments to bitmap data and thr...
Merge branch 'nat' of github.com:mozilla/shumway into nat
Set mouseOver/mouseDown properties and advance button states
Support button mode
Type fix
Revert previous font resolution fix, restore @mbx's version
Add missing semicolons when escaping static text
Merge pull request #1473 from tobytailor/nat

Misc
Change `grunt avm1` and `grunt flash` to also build the relevant .abc files

... in parallel. If the `.as` files didn't change, then this doesn't take any time at all, and if they did, not building the `.abc` files is wrong.

Also removed the `playerglobal` and `avm1lib` aliases, as they're now subsumed in `flash` and `avm1`, respectively.
Merge pull request #1474 from tschneidereit/nat

Change `grunt avm1` and `grunt flash` to also build the relevant .abc files
Remove default argument from MovieClip#_gotoFrame

All callsites can pass in proper values for the `scene` argument easily.
Change AVM1's ifFrameLoaded function to not return false forever if the requested frame is > totalFrames
Merge pull request #1475 from tschneidereit/nat

Change AVM1's ifFrameLoaded function to not return false forever if the requested frame is > totalFrames
Clipping fix. In Flash, masks that clip nothing should not be visible. In the GFX backend, there was no way to express "clip nothing". This patch fixes that.
Merge branch 'nat' of https://github.com/mozilla/shumway into nat