* restore a subset of the rand module

* flake

* remove cleanup, go ahead and assume status will always be 1

* lighten and add power

* Fixed #657 -- handle OverflowErrors on large allocation requests

* always be overflowing

* Drop the deprecated rand.egd function

* Removed egd tests

* Removed egd docs

* Document the removal

* unused imports

* Update CHANGELOG.rst

Fix up the assert helpers, subclass form `object` rather than test case,
and use parametrization where appropriate.

One helper method on the original `TestCase` was the ability to create
temporary directories that were cleaned up at the end of the test --
now we use a pytest fixture instead: http://doc.pytest.org/en/latest/tmpdir.html

Addresses #340.

Also harmonize documentation.  #boyScout

Prevents accidental imports when running tests.