Auto generate the allocation_scheme

[Permafacture]

Right now, laying out the components such that they are all contiguous given the entity classes that one will use must be done manually. It's easy for a human, but would be cleaner if it was done automatically. Situations where contiguous components aren't possible aren't allowed currently, and allowing for these situations would both difficult and precarious from a performance perspective. More thought is needed to deal with that.