Sandcastle cleanup.

* General cleanup, reformatting, refactoring, code standards, etc.
* Fixed package configuration for both Dojo and RequireJS
   * By using the right baseUrl, we don't need to list all the packages
   * Dojo config is supposed to be defined as var dojoConfig, RequireJS config is supposed to be done with require.config
* Centralize CSS that all examples use in a shared bucket.css
* Fix the loading display
   * Separate it from the toolbar
   * Implement it as a more visible overlay which is shown/hidden via CSS
   * All examples have a sandcastle-loading class on their body which can be used to hide other UI while loading
   * Instead of having to set the toolbar's innerHTML to '' randomly before putting buttons there, examples now call Sandcastle.finishedLoading(); at the end of the function, which more clearly describes the intent
* Disable the keyboard input for the Dojo TabContainer that holds the JS/HTML editors so that ctrl-home and ctrl-end work like they're supposed to
* When switching tabs between JS/HTML, focus the editors automatically
* Copy all attributes from the example's body onto the bucket's body, instead of just class/title, and use regexes instead of fragile indexOfs
* Clean up and simplify examples themselves, and only use the Dojo modules we need.
* Fix Skybox in a number of examples.
Merge remote-tracking branch 'origin/master' into sandcastle_cleanup
Produce a built version of CesiumViewerWidget.

The "Cesium Viewer" application is not what people should be using in their own "applications" (simple though those applications may be) that want to use the widget.  So, create a built layer for the CesiumViewerWidget, allowing clients to require that in and recieve all dependencies, allowing them to construct a CesiumViewerWidget instance however they like and put it whereever.
Merge pull request #500 from AnalyticalGraphicsInc/buildWidget

Produce a built version of CesiumViewerWidget.
CSS cleanup: Convert tabs to spaces, fix dividing line between .top and .bottom.
Add loading to jQuery UI example, and make it look like the others.
Merge remote-tracking branch 'origin/master' into sandcastle_cleanup
Re-export all Sandcastle demos.  Three were missing the `sandcastle-loading` class.

Even if a particular demo doesn't need this class, it should still
be included for consistency with the bucket, so that when a user
modifies and re-exports it, the only diffs will be user mods.
Show loading message in Hello World example.
Merge pull request #497 from AnalyticalGraphicsInc/sandcastle_cleanup

Sandcastle cleanup.
Merge remote-tracking branch 'origin/master' into playback