New: updated jQuery knob.

Wanted to see if it supports a step size less than 1, which it doesn't, but it's still good to have it updated.
New: RKRotate.js and basic server.

- RKRotate sets up a canvas element that rotates the image inside, it doesn't use much from rotate.js, it doesn't use kinetic
- Refactored into preferred jQuery plugin style
- More precise than previous version (1.0 degree step is much too big.)
- Sends JSON
- Needs grid (#117)

Refs #179