Increase the length of the player input buffer

This simply changes the value of BACKUPTICS from 32 to 96 (a little less than 3 seconds), causing the game to buffer inputs for a longer time before freezing.

This should have three main advantages:

1. Players with high latency are less likely to lag everyone else in the server.
2. Players joining during a netgame will pause the game for less long (2 seconds less probably).
3. Short game/internet freezes are less likely to affect everyone else in the server.

I can't wait to play SRB2 with 2500ms ping!

merged

mentioned in commit c43ca31d

mentioned in merge request !949 (closed)

mentioned in merge request !950 (merged)

mentioned in merge request !951 (merged)