Removed Rake support and handling

Removed the auto-generated rake task stuff and reworked the README
to remove all rake mentions and set up for more CLI and configuration
documentation.

@jcredding this is ready for review (>500 removals - booyah!)  Feels good.  The README diff is rugged - completely reordered the section to put usage stuff on top and definition/reference stuff on bottom.  I'd just read the file straight-up.