Minor formatting and clean ups.
Updated EIP/PCCC code.  PLC5 read and write for INT and FLOAT now work.  And arrays.
Added new example, plc5.c, to show how to talk to a PLC5.

Note that timers and counters and other structured data is not tested.  May not work.

Reading booleans (B3:8 for instance) works, but gives you back all 16 bits.  Writing
booleans is untested.