Adds regression test for issue #259.
Fixes #259.
Cleanup and docstrings.
Fixes Py3 related bug regarding dictionary element ordering.
Wrap lines.
Adds messages to ValueErrors in client_maps.py
Merge branch 'master' into bugfix/from-dim-data-regression
Merge pull request #263 from enthought/bugfix/from-dim-data-regression

Correct handling of irregular block arrays in `Context.from_dim_data`