* Fix thermal protection documentation.
Even before the recent thermal protection changes, the documentation of
the thermal protection feature in the config files did not match the
implementation. I fixed the documentation and reconciled the M303
implementation with the documentation.
* Applied documentation changes to sample config files
* Renamed hysteresis to watch_temp_increase
* Added gcodes back into documentation.
Changes to support NEOPIXEL LED strips
- Support for different NEOPIXEL as defined in Adafruit_NeoPixel.h
- ability to setup startup brightness
- ability to define sequential/non-sequential transition of color change during heating-up
- additional parameter to M150 P<brightness>
