Refactor Sandcastle to avoid require boilerplate in the code editor.

The code in the editor is automatically surrounded with code to require in the Cesium module.  This removes the need for other buckets except Dojo (for now).
The gallery HTML files can be hand-edited to use a combined Cesium.js file simply by removing the RequireJS scripts from the head and inserting
a script tag for Cesium.js.
Various other cleanup in the Sandcastle code itself.  Gallery files are reloaded from the server when clicking them now, previously the contents would be cached in memory.
Clear undo history after loading a new demo.
Update CHANGES
Remove bucketTitle.  Fix QuadtreePrimitive example.
Merge remote-tracking branch 'origin/master' into refactorSandcastle

Conflicts:
	CHANGES.md
	Specs/Sandcastle/QuadtreePrimitive.html
fix typo
Merge remote-tracking branch 'origin/master' into refactorSandcastle

Conflicts:
	Apps/Sandcastle/gallery/CZML.html
Merge branch 'master' into refactorSandcastle

Conflicts:
	Apps/Sandcastle/gallery/3D Models.html
	Apps/Sandcastle/gallery/Billboards.html
	Apps/Sandcastle/gallery/CZML.html
	Apps/Sandcastle/gallery/Camera.html
	Apps/Sandcastle/gallery/Labels.html
	Apps/Sandcastle/gallery/Materials.html
	Apps/Sandcastle/gallery/Polyline Color.html
	Apps/Sandcastle/gallery/Polyline Material.html
	Apps/Sandcastle/gallery/Polyline.html
	Apps/Sandcastle/gallery/Simple Polyline.html
	CHANGES.md
remove stray Circles and Elipses picture
whitespace cleanup
Fix line numbers for highlighting and errors.
Fix line numbers in Firefox which are zero-indexed.
Trim whitespace from the start of the HTML editor contents.
Only insert an extra line for Firefox when applying the bucket, not when jshinting or saving the file.
Fix scrollToLine
Merge pull request #1903 from AnalyticalGraphicsInc/refactorSandcastle

Refactor Sandcastle to avoid require boilerplate in the code editor.
Merge remote-tracking branch 'origin/master' into gltf-8