Allow Lua scripts to more easily reference the player's mo while spectating
Players still have an mo when spectating, but this is arbitrarily unlinked. Currently the only means I have of finding this mo is through a costly mobj.iterate() function.
I realize that changing how player.mo functions will break script compatibility, so maybe as an alternative we can create "player.truemo", which will always link to the player's mo even if the player is spectating.