Add SquareRenderer demo.

Fix slight issue with plottable.css.
Add a getter/setter for whether or not to show end ticks on an axis. Needs work...
Set size on SVG in scatterplotSquare example.
Fix #221
Work on building the homepage
Fix #221
Update plottable.js, plottable.d.ts, and other build artefacts
Merge branch 'master' into gh-pages