P25 Activity Summary - add summary of observed talkgroups

[DSheirer]

Add support to capture all talkgroups and radios (like MPT1327 currently does).

Activity summary should show an alphabetical listing of all TO talkgroups and the individual radios that called them and a complete listing of all talkgroups and radio IDs that were active thus far.

[jpryor223]

include first heard/seen, last heard/seen, call counts, basic stats, basically utilization data (call type: normal, encrypted, phase 1 versus phase 2)