Add proper keyboard detection to Flash/AIR.
Quick fix.
Remove unused member.
Always clear to black.

Or in HTML's case, don't clear at all.
Change the SWF background color to black.

Fixes #102. I originally thought this would never be seen, but it's used
before the SWF is fully loaded (and the Stage3D context is grabbed).
Maybe it could be configurable later, but for now black is way better.
Merge branch 'master' into haxe3

* master:
  Change the SWF background color to black.
  Always clear to black.
  Remove unused member.
  Quick fix.
  Add proper keyboard detection to Flash/AIR.

Conflicts:
	src/flambe/platform/html/WebGLRenderer.hx
HxSL2 fix.