Add ipython_utils module
Remove some IPython entry points.
Add close method to Context.
Use new Context.close() in TestContext class.
Merge pull request #241 from cowlicks/ipython-cleanup

Remove some IPython entry points.
Add DistArray creation module creation.py
Add test module for creation.py
Remove DistArray creation tests from test_client.py
Reflect DistArray creation API changes in distarray/*.py
Reflect DistArray creation API changes in distarray/tests/*.py
Add creation imports to __init__