#29 Add ability to PWM incandescent bulbs

[OPP]

Title says much of it. Commands also need to be written so that the PWM level can be set for the individual lamp. DMDs are updated every 2 ms, so that seems to be a good rate for persistence of vision. Maybe support 8 levels. It would be good to stripe the information, so 50% PWM would be 10101010 instead of 11110000 which would give more severe blinking.