This is a replacement for PwmPin(). It keeps track of channel numbers internally, which greatly simplifies the user interface. Starts by using the 8 Low Speed Timer channels and then moves to the 8 High Speed Timer channels if more than 8 LedPins are instantiated. Throws a non-fatal error if more than 16 LedPins are instantiated, and ignores any attempts to set the duty cycle of those channels.