Erase using Shift. Display saved data locally (console). Select color by pressing space only once.

Hi there. Awesome tool!

Please review the following changes I've made:

* Users can now draw and erase without toggling between 'b' and 'e'. Erase blocks by holding down Shift while drawing.
* Users can now press Ctrl+Shift+S, and display the data locally (console) rather than post to a Gist.
* Quicker color selection. Users can now press Space, select a color and the color palette automatically fades out.