GRAPHICAL-PLAYGROUND: Rearranged the header for better use of screen real estate.
Upgrades CodeMirror and switches to lint-checking version.
Merge remote-tracking branch 'abledaccess/graphical-playground' into graphical-playground

* abledaccess/graphical-playground:
  GRAPHICAL-PLAYGROUND: Rearranged the header for better use of screen real estate.

Conflicts:
	demos/interactive/css/playground.css
Fixes CodeMirror linting support.
Adds throttle for valid change events.
Temporarily moves #gfx back up to the top of the page.