Fix fox #542, indicate font licenses

I just implmeneted the native Metal port of NanoVG. ;)

Highlighted the need for render target stencil buffer.

- added projects section to read me
- added processing API link (issue #135)

- added documentation about changed GL state
- made old GL2 and GL3 backends obsolete

- moved demo stuff to separate file
- created two separate examples for gl2 and gl3
- initial stab at OGL 3.2 core profile back-end (currently twice as
slows as 2.0)
- API change: glBeginFrame() takes view witdth and height as input
- added FPS counter to demo

- fixed arc rendering for small arcs
- added color wheel to example
- added screenshot

- removed unused files
- added license
- added readme stub