Merging with upstream

Skip things we shouldn't be testing

Fixing misc testing related things.

Adding information about IPYTHONDIR to usage of ipcluster and friends.

Addressing various review comments.

Merging Fernando's fixes to test_iplib.py.

Fix tests when run outside iptest.

Ensure that we don't damage the __builtins__ object after %run. This fixes lp:364853. Also added a standalone set of testing.tools utilities that can be used in place of nose.tools to get proper test generators in object oriented tests.

Add a few tests for ipdoctest itself. Not very complete yet, but a start.

Add tests to ensure that %run does not modify __builtins__ I will open a ticket for this, the current code only has the failing tests, I still need to find a fix.