WIP hacking to make Cesium run in IE11.
More hacking.
Closer to working...
Eliminate forward declarations.
Make a very basic and broken globe show up.
Re-add code that doesn't break anything.
Re-enable web worker.
Merge remote-tracking branch 'origin/fixWeakmapShim' into ie11

Conflicts:
	Source/Core/loadImageViaBlob.js
Merge remote-tracking branch 'origin/master' into ie11

Conflicts:
	Source/Scene/CentralBody.js
	build.xml
Use Bing imagery again.
Work around near-plane clipping problem.
Remove workaround.
Remove some more workarounds.
Remove more workarounds.
Remove sampler array workaround.
Remove more workarounds.
Remove more workarounds.
Re-add BuiltinFunctions.glsl.
Remove some workarounds.
Remove tile discard policy workaround.