Removed dangling references when picking
Merge branch 'master' into leak
Merge branch 'master' into leak
Merge branch 'master' into leak
Merge branch 'master' into leak
Merged master to leak
Merge branch 'master' into leak
Merge remote-tracking branch 'origin/master' into leak
Merge branch 'master' into leak
Merge branch 'master' into leak
Picking JavaScript improvements
Rename `HelloWorld.html` to `index.html`

Also add Chrome Frame tag to Hello World so it works in IE if GCF is installed.

This change was largely a result of some end-user usability feedback in a recent Cesium hackathon.
Fix ellipsoid picking
Added ellipsoid picking test for alpha = 0
Updated CHANGES.md
Moved Noise to BuiltinFunctions.  Added material-correct picking to Polygon
Added generic function for creating fragment shaders for picking
Added material-correct picking to polylines
Add index.html for the small release zip.
Update Cesium.js index.html with external links.