Config options mapped to symbolic names (6.1.8)

[ngjunsiang]

IEEE1278.1-2012 has a section (6.1.8) on fixed and variable parameters defined prior to an exercise in an exercise agreement.

Some of these parameters affect the packing, transmission, and receipt of PDUs, e.g. tolerances of ESPDUs, MAX_PDU_SIZE_BITS/OCTETS.

I'm putting a placeholder issue here for when we eventually get round to setting up config, as a reminder to refer to this section for option names.