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.