minimum Vcc is now 3.3[V] (3x1.1 == 3x low-power eneloops)
low power handler has been reworked to have check and halt() calls separate, to allow user's code to be added, before halting
added low power handing code to main()
minor style and comment fixed + constants improvements
class for watchdog handling
watchdog added to main code
most TODOs marked as done (or removed)