added fan control via M206, added functionality for M66 waiting on temperature

M66 now can wait for temperature of hot-end being within a temperature window
temperature to be set by M104 (reprap style)
M66 P0 L3 Q100 will wait for the temperature before continuing
Above functionality is the same as the reprap M109 command.

M206 can be used to set the speed of the fan

added a file for testing above function