Added addr, auto, and clr prologix cmds

First commit of adding prologix command set support
Added prologix ++eoi cmd

This command still toggles both reading and writing EOI use, which is not the same as prologix
Added prologix ++eos cmd

Two character EOS (++eos 0) does not work for receiving
Added 2-char terminator support
Removed todo for eos
Added prologix ++eot_enable cmd
Will now append EOS char even with EOI used
Fixed bug in last commit with double EOI asserts

If eoiUse was true, EOI would be asserted on both the data and the termination characters, which is wrong.
Added prologix ++ifc cmd
Added a line comment
Added prologix ++eot_char cmd
Moved target listen cmds to function "addressTarget"
Changed ++eot_char to return an int

This way it is consistent with the way you specify it
Added prologix ++llc cmd

This is the local lockout cmd that prevents the front panel of the currently addressed model from working
Added prologix ++loc cmd

This is GPIB cmd GTL for "go to local" and re-enables the front panel of an instrument that has been locked out via ++llc
Added dummy ++lon cmd

Currently does nothing, but ++lon will be used for "listen-only" mode to sniff the bus
Added dummy ++mode cmd

Will be used to swap between controller and device mode, currently only controller mode works
Added basic version of prologix ++read

Currently accepts ++read (read until EOS condition) and "++read eoi" (read until EOI asserted) which is slightly different than the prologix implementation
Added the string buffers for all remaining commands

None of them do anything yet
Added ++rst and ++ver cmds