Remove some unused cruft.
One character fix to close issue #258.

Also a small PEP8 change.
Refactor make_grid_shape and optimize_grid_shape to 1 thing.
Remove test for unused function
Add tests for new 1's in grid_shape stuff.

Some PEP8 too.
Remove duplicate test.
Remove incorrect docstring.
Add tests with prime cluster.
Remove unused functions, divisors and outer_zip
Add LocalArray.base, .ctypes
Merge pull request #274 from cowlicks/make-grid-shape-work

Allow and test 1's in `grid_shape`
Mock out imports for building api docs.
Add missing modules.
Merge branch 'master' into bugfix/api-docs
Fix formatting in from_global_dim_data docstring.

Sphinx doesn't like subsections under the main sections.
Fix a bad automodule reference.
Fix example formatting in plotting docstring.
Fix docstring formatting in make_grid_shape.
Fix return value formatting.
Fix formatting of other Raises section in format.py.