This fixes assorted Sphinx documentation stuff:
1. Add CSS workaround for horizontal stacking glitch in rtd theme
2. Convert plain comments for public constants to doc-comment style
so they will get included in the html docs
3. Change Sphinx autodoc's default sort order from alphabetical to
groupwise. Now the class methods come first, the properties come
next, and the constants go at the end. It's much easier to read
this way.
