Detail for my Mk2_bothDisplays_2.ino sketch

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

The display can be driven in either of two ways.  A #define statement 
near the top of the sketch can be either included or commented out to 
achieve this selection.  If no display is in use, it doesn't matter 
which way the display code is configured; the driver logic will just 
rattle away in the background, un-noticed by the rest of the world.

The two powerCal variables provides a convenient means of calibrating 
hardware for use with a Mk2 Router.  CT1 and CT2 each have separate 
powerCal variables, with the suffices _grid and _diverted respectively. 

Changes for version _2:
- for compatibility with other versions of the Mk2 code, the variable cycleCount 
has been removed.  This variable would have eventually overflowed which 
could have caused unpredictable effects with other versions of the Mk2 code.

- improved description of the display code initialisation in setup() for the 
pin-saving hardware option.

- removal of some unhelpful comments in the IO pin declaration section.