Function-adjustable environments

[OAGr]

It seems like it will be often when we'll want to run some sub-function with a lower sample count. For example, if we want to integrate a function by calling it at n different points, we might want to have a high n, but a low "sample count per point".

I'm not sure how to best do this. One method would be having some functions be able to change the global variables, but I'd assume that's tricky with the reducer. Like,

foo = SampleSet.fromDist(normal(5,2))

@globalChange("sampleCount", 200)

bar = SampleSet.fromDist(normal(10,3))

....

A different thing we could do is allow functions to accept custom environment over-rides. This is a bit tricky because those over-rides might need to last for each subfunction of those functions.