Upgrade RequireJS to version 2.1.6, and Almond to 0.2.5.

Also additionally include the minified version of require.js, useful for future builds.
Merge remote-tracking branch 'origin/master' into updateRequireJS

Conflicts:
	CHANGES.md
Fix path to almond.
Merge branch 'updateRequireJS' into viewer
Avoid creating two BingImageryProviders so we don't hit the Bing service twice on startup.
Switch build process for CesiumViewer to no longer use Dojo.