Add a `stop` command to the script.
Rename `run_ipcluster` to `ipcluster`.

Since it now has start and stop commands.
Add a module docstring.
Change the default number of engines to 4.

Only 4 are needed for our current tests.
Update the Makefile targets to match.
Wait until 'success' is printed.

Really, the longer string about engines starting successfully.
Remove 'sleep'--should no longer be necessary

... since the `start` command now waits for success.
Support bool comparisons on dist and local arrays.
Allow distarrays ufunc's to take the standard numpy kwargs.
Test boolean comparisons.

This also corrected a lot of tests that were being missed, and pep8'd
the files I was working in.