more flexible way to specify slots to commands

This allows you to specify slots like this using commands /kick, /away, /spec:

/kick 4     # kick player 4
/kick 5-6   # kick players 5 & 6
/away -3    # toggle away state for players 1-3
/spec 5-    # toggle spectator state for players 5-8
/kick -     # kick all players
/kick *     # kick all players

Merge pull request #201 from rherriman/lower-cpp-reqs

Try to fix issue on 10.13 and 10.14

Merge pull request #201 from rherriman/lower-cpp-reqs

Try to fix issue on 10.13 and 10.14

improve RTT calculation by command type

* ping messages weighted more, helps to set a better initial RTT value
* roster messages weighted more before a game starts, helps to set initial LT value via chat messages
* key&mouse messages weighted as before, affected by frame rate.

Fix tracker link

replace Byte with uint8_t