Reflecting the fact that DCC++ works on both the Uno and the Mega

Added <J> and <J ID> command to set/show server ID [1-120].
Added to EEPROM storage, with default=1

* DCC++ MASTER = WIRE Address 0
* DCC++ BOOSTER = WIRE Address 1-119

Remote sensors configured on DCC++ BOOSTERS can now be read from the
DCC++ MASTER.  Define sensors with unique IDs on BOOSTERS and they will
be automatically uploaded to MASTER and MASTER will keep track of
status.

Added Remote Output functions and ability to transit <Y> commands from
DCC++ SERVER to DCC++ MASTER.

Use <Z ID ACTIVE> for both local and remote OUTPUTS.  For remote
OUTPUTS, ID should have already been defined on respective DCC++
SERVERS.

needs to be completed so that per-server requests are made using <G ID>
command, instead of general call.

successfully created server receiver mode

No longer using Wire Library - instead, created custom, non-blocking
interrupt routing that implements Master Transmitter and Slave Receiver.

Problems with general call address and <G> command needs to be
explored.  Also need to incorporate all potential error modes into
interrupt routine.