Fixes machines being able to put the Radio Controller to sleep + Radio Controller cleanup

Before if a machine decided to sleep() in response to receiving a radio signal, it would put the radio controller to sleep. The most notable case of this being doors, which forced the radio controller to wait until the door was done opening or closing before sending the signal to the next machine.
Do you think ```spawn(0)``` is to blame here? This and factoring out code into ```send_to_filter()``` were the main changes I made.