style fixes

[wholmgren]

Here are a bunch of quick and easy style fixes. We are still a long way from perfection, but this should take care of many of the issues identified by LGTM and most other PEP8 issues aside from variable names.

• Closes issue #xxxx
• I am familiar with the contributing guidelines.
• Fully tested. Added and/or modified tests to ensure correct behavior for all reasonable inputs. Tests (usually) must pass on the TravisCI and Appveyor testing services.
• Updates entries to docs/sphinx/source/api.rst for API changes.
• Adds description and name entries in the appropriate docs/sphinx/source/whatsnew file for all changes.
• Code quality and style is sufficient. Passes git diff upstream/master -u -- "*.py" | flake8 --diff
• New code is fully documented. Includes sphinx/numpydoc compliant docstrings and comments in the code where necessary.
• Pull request is nearly complete and ready for detailed review.