Detail for my Mk2_multiLoad_CAT5_2.ino sketch

This is an upgraded version of the original Mk2 sketch for use with my
PCB-based hardware.  It still supports two current sensors, CT1 and CT2.  
CT1 is for monitoring the flow of energy at the supply point; CT2 is 
available for monitoring the flow of current to the primary dump-load.  

With this version, multiple dump-loads are supported, each being 
controlled by its own dedicated IO pin.  To generate sufficient spare
IO pins for this purpose, the RF facility has been removed from this code.
By using the pin-saving hardware option, the 4-digit display is still 
available for use.

The primary load (Load 0) is still controlled from the "trigger" port.  The 
five IO drivers that have been freed up by not using the RF module have been 
re-allocated to control five additional loads.  These signals can be 
conveniently accessed at the left-hand side of the J1-5 connector on the PCB.  
The uppermost pin is for Load 1, the lowermost one is for Load 6.  

For compatibility with previous versions, all loads are driven using 
active-low logic.