new chatbox

[Razish]

can grab most features from ja++

• move input to cgame
• scrollable (mouse wheel, pgup/pgdn)
• input history, tab completion for names, etc (depends on input fields - reimplement contextual completion #1)
• clickable URLs
• clickable player names to bring up a menu with actions like whisper, ignore, force team red/blue, callvote kick, etc
• text selection improvements?
• tabbed chatbox?
  • tabs for global/team/PMs, or PMs only
  • option to expire inactive whisper tabs after X seconds
  • option to sort whisper tabs by activity
• "mode switcher" like MMOs, where /t blah will switch mode to team and latch until it's changed again, /w raz<tab> will open a new PM to "Razor" (when sent)