Reduce timestamp resolution to minutes.

Fixes #88.
Correct changelog date.

Fixed #92.
Clean up some imports.
Include source file name/path when a post rename fails due to a conflict.

Fixed #89.
Removed propane_distribution submodule.
Squashed 'propane_distribution/' content from commit f276bb9

git-subtree-dir: propane_distribution
git-subtree-split: f276bb9ad4b048d136f726b7fa23b6ee5ec17323
Merge commit '5a4b6411dd9b8a29062d0dffc3eff1b7f1f3b650' as 'propane_distribution'
Update PyCharm config since propane_distribution is no longer a submodule.
Reorganize theme files so fewer files are copied during a build.
Fix bug found by code inspection.
Refactor theme class to handle copying content itself.
Add dev tools to list and compile themes.
Add support for precompiled stylesheets.
Update readme.