Warn inactive game hosts and eventually remove them from game listings

[GrantBartlett]

Removing inactive hosts from game lobbies

In relation to this: https://github.com/CnCNet/xna-cncnet-client/issues/88

• Checks the host hasn't been active for X seconds (default 180)
• Continues to check on past that time until X seconds (default 240) until the host is automatically removed from their game.
• Disposes of checks when in game, and reactivates when back

Improvements

• Wanted to check that everything is being disposed of correctly
• Probably needs to be listening to the global mouse handler (if that even exists, e.g window.addEventListener("mousemove",.. in JS land).
• Should probably also listen to Keyboard events