Rename 'entry' to 'iter' inside netpeer iteration; makes more sense
First try at serverside player command limiting (AKA TIC buffer)

Be consistent in use of `command_index` instead of
`latest_synchronized_command_index` in cl_predict

Add "limit_player_commands" config option

Extent netpeer's command sync to keep track of both commands received
and commands run

Send both received and run command indices over the wire
Fix players not receiving commands for other players

Commands were stacking up serverside; fixed
Disable sound & sync debugging; update TODO.md
Rebuild tags
Make clientside player position extrapolation optional

Remove extra/missed TIC processing from clientside prediction
Fold sv_tbuf into sv_main