Added rectangle rendering

Strokes, fills, transparencies, line colors all work
No physics yet
Fixed lineWeight and added a rectangle API
Some functions in the API:
Added layering, support for custom colors
Instead of three color channels, there is one string, which is directly put into the SVG's attribute (Check for security)
This allows for alpha for stroke.
Rectangles can now be in front and behind the physical objects.
Rectangles can now be fences

Originally called reflection, now called fences to be more understandable
Changed some defaults and fixed some bugs

Now all the tests pass, and the absorption interactive works!

Also general jslint cleanups.