Codegen does not allow neighbourhoods to be be referenced in functions

[NicEastvillage]

In code gen neighbourhoods are constructed by calling a function. That function requires a world view, and that world view is a local variable passed to the function that evaluates the state logic. So if the state logics calls a custom or builtin function, the world view is no longer available.

We can solve this by making each local neighbourhoods to global variables.