Missed a Weapon HUD sound.

Removed Gravity Gun sounds and Weapon HUD sounds.

Removed Gravity Gun firing sounds (for now), added proper Cleanup, Jump and Pistol sounds.

Note: Since the Cleanup and Jump sounds required additional scripting, they will not actually be heard in other servers unless the server has the addon. The only other way to get the Cleanup sound to work is if the server allows clientside code to be ran. Jump sounds will not work even if clientside code is allowed, since it's serversided. (Unless I can figure out a reliable way to have them play clientside.)

Addon was created.