Merge branch 'terencehill/ready_restart_tweaks' into 'master'

Terencehill/ready restart tweaks

Improve behaviour when sv_ready_restart and sv_ready_restart_after_countdown are enabled:

* Don't play "Prepare for battle" announcement twice in games made of rounds

* Block players while the countdown to game start is going even if sv_ready_restart_after_countdown is enabled
This is to avoid that a player roaming in the map gets confused by the sudden respawn when the game begins; it also helps to more clearly separate pre-game time from pre-round time (in the latter players are allowed to move depending on the game mode, e.g. CA allows it, FT doesn't)

See merge request !88