Add coop on/off functionality

[Endernice61]

Added enum for player teams in portal_man.nut
Added PortalGun class to store information about what portals the portal gun can shoot with method to apply it to an actual weapon_portalgun
No longer waits 2.5 seconds to find players as this method does not work for published maps
Added on_blue_spawn() and on_oran_spawn() which gets called when the bots respawn, or shortly after the bots spawn for the first time. Retrieves the handles for the players' portal guns and sets their kevalues appropriately
_find_players() will now call in_hover_phase() and register the callback function on_death(player, dmgtype) for BotDeath
Added in_hover_phase() which waits until bots are able to move, then calls on_blue_spawn() and on_oran_spawn() to set up portal gun keyvalues
Added on_death(player, dmgtype), which calls waitForBlueRespawn() or waitForOrangeRespawn() depending on the bot that died
Added waitForBlueRespawn() and waitForOrangeRespawn(), which waits until the bot no longer has 0 health, then calls on_blue_spawn() or on_oran_spawn(), respectively
init(blue, orange, has_onoff initializes PortalGun classes for both bots and calls waitForPlayers()
Added waitForPlayers(), which waits until the players handles can be retrieved with vscript, then calls _find_players()
return_pgun() will set the bots' portal gun's keyvalues
Added set_gun(pgun, team) to set a bot's portal gun to match pgun
pgun_btn_deact() and pgun_btn_act() now update bots' portal guns
Added set_pgun_keys(gun) to set keyvalues on spawned portal guns in singleplayer