Add Set#pick and Set#pop
A very common operation on sets is to take an arbitrary element from them at O(1) cost. I know typically
it's suggested that library additions go out as a gem to see community review. However, to me it seems
to be a glaring omission to lack such an operation on a built-in, fundamental data structure, so I've
gone straight to the bug tracker.
I wasn't too sure which method names to use as I've often heard "take" in lieu of "pop," so I just used the
names Wikipedia uses. Consider them flexible. "Pick" selects an arbitrary element, and "pop" selects and
I've provided a very simple patch that implements the necessary behavior. Thoughts?