Performs miscellaneous tidying. No functionality alterations.

 - Migrates appropriate comments into docstrings.
 - Minor white space tweaks around non-argument = operators.
 - Adds additional editor files to .gitignore.
 - Attempts to disambiguate some functions in timeutil.py.

Of these, the last is that of which I am least certain. The logic and assumptions around convert() in particular could use your own documentation.