Add osdp_FMT to CP for backward compability

[rherrmannr]

osdp_FMT has been removed (see #206).

For backward compatibility, it would be preferable to continue supporting osdp_FMT. @rsgmodelworks suggested the following approach:

If you want to be gentle about it, you could disable it when the PD reports an OSDP version capability 4 (See section B.17, capability 16 value 4 means "SIA 2.2.2".)

Otherwise, libosdp will effectively support only the latest standard. Some form of version handling is required to maintain backward compatibility with older OSDP PDs that still rely on.

[rsgmodelworks]

There are no known implementations of osdp_FMT in the wild that I know of (I do OSDP Verified inspections, I have probably seen at least 2 dozen implementations if not more.) As far as I know nobody has approached the SIA Technical Committee disagreeing with long-standing consensus to remove it from the spec. If you know of implementations in wild then of course your logic applies. If possible could you please identify the implementations that use this?