Adds a default stylesheet with actual CSS in it for generated apps.  Previously, the _theme.css stylesheet would be created, but since it has no actual styles once it has been processed with Sass, there would be no actual stylesheet.css built.  The result would be that app/current/stylesheet.css would be linked to in index.html and not found.

Also removes deprecated textAlign property and adds some tips and notes about how to style apps.
Adds more helper text including where to learn about configuring the Buildfile, to the Buildfiles.
Fixes bad example that references a non-existent property on the namespace rather than performing a query and removes the same bad example from statechart app.
Fixes wrong @extends jsdoc from SC.Object to SC.ObjectController.  Also removes dangling commas.
Cleans whitespace.