Tweak E2D model to allow one glass block

Hacky addition assumes one single glass block that is
set once and doesn't change. This is to allow that block's
state (internal temperature) to remain in place even after
a model update, which would otherwise re-create all blocks.

This hack will not be necessary after E2D is changed to support
moving existing polygons.
Add show-shapes toggle
Add model saving and loading
Add simple drawing of objects to Energy2D model

This doesn't update Energy2D, it simply adds a canvas
in front of the model that we can use to draw new
rectangles in the model.
Add state to draw button
Style public page header
Update to use non-buoyant (top-down) model with probes
Initial version of pure-js energy-2d interaction
Add simplistic sample-based calibration
Separate capture and process, and auto-process every 3 sec
Add arduino example
Add simple mock-up of a Grid Game

This game is designed to support a paper-prototyped
card game about energy trading.
Merge branch 'master' into gh-pages

Conflicts:
	energy2d-demo.html
	experiments/opencv-nodejs-energy2d/.gitignore
	experiments/opencv-nodejs-energy2d/app.coffee
	experiments/opencv-nodejs-energy2d/client/style/style.css
	experiments/opencv-nodejs-energy2d/client/video-processing.js
Add grid game to gh-pages