Pull threads out of functions

[Hdt80bro]

Several functions define anonymous thread functions like ForkThread(function() ... end) which are low-hanging fruit to adding customization points by naming them. These threads are something that, were a mod were to want to change, would require replacing the entire function in addition to the thread function. This is unnecessary on our part, and increases such a mod's stiffness - which I have seen cause at least some parts of one mod to cease to function. While this won't help with anything already written, it is possible to prevent future bit rot.