Move usercmd_t creation to cgame

Add CG_CREATE_USER_CMD, usercmd_t creation is game dependent.
Add CG_JOYSTICK_EVENT, needed for creating usercmd_t.
Add FloatAsInt and IntAsFloat to q_shared as they were being duplicated all over.

Remove delta_angles from sharedPlayerState_t, used for centerview command that was moved to cgame.
Remove trap_SetUserCmdValue, now cgame creates the usercmd_t so it's unneeded.
Remove cl_debugMove. (should consider readding later.)