Redo local random array creation

Redo `LocalArray` creation in `local/random.py` and update the client-side `random.py` to call the new functions correctly (giving them a local `Distribution` object).  Partially addresses #341.

The client-side code could use some work; the string-based calling is pretty verbose; however, I'll wait on the new `apply_async` strategy for that.

Based on #340 and #342.