Update to Dojo 1.8.3

1. Delete `ThirdParty/dojo-release-1.7.2-src`
2. Add `ThirdParty/dojo-release-1.8.3-src`
3. Update source with find and replace.

No other changes
Update CHANGES
Update the sky box to use the correct orientation.

Also added a `skyBoxBaseUrl` parameter to the widget, for easily
swapping out different sets of SkyBox images.
Merge pull request #488 from AnalyticalGraphicsInc/stars

Update the sky box to use the correct orientation.
Use when-fu to eliminate lots of tricky code.
Update frame state in render instead of initializeFrame.
Update erosion picking example.
Rework Dojo build process and make it work with the new version.

The CesiumViewer app is now built into its own layer instead of using dojo/dojo.js.  Rename boot.js to CesiumViewerStartup.js and move all code out of there.  It only exists to set up the package config.  Reduce the number of files in the built output by deleting stuff we don't need, and modules that are already included in the app layer.
Merge pull request #491 from AnalyticalGraphicsInc/pickingExample

Picking Example
Update CHANGES.md
Merge pull request #492 from AnalyticalGraphicsInc/loadCubeMapCleanup

Simplify and improve loadCubeMap function
Make Transforms (with default EOP) usable in Internet Explorer.
Merge pull request #493 from AnalyticalGraphicsInc/eopOnIE

Make Transforms (with default EOP) usable in Internet Explorer.
Merge remote-tracking branch 'origin/master' into dojoUpdate
Update getFrameState doc.
Merge pull request #490 from AnalyticalGraphicsInc/frameStateUpdate

Frame state update
Merge remote-tracking branch 'origin/master' into dojoUpdate

Conflicts:
	CHANGES.md
Merge pull request #486 from AnalyticalGraphicsInc/dojoUpdate

Dojo update
Merge branch 'master' of https://github.com/gbeatty/cesium into videoWithOverlay