Changed BaseMapping to a less generic name

Now: JSONableDict!
Removed 'version' silliness, added CLI TestCase

Instead of moving the version package around with setup.py magic, I went with
explict ImportError handling, throwing warnings when things fail and otherwise
relying on setup.py's install_requires/tests_require to do all the hard work.

The CLI TestCase implements all of the ideas put forth in the TODO comment,
which were apparently all good. Woot.
Added/changed many things. Megacommit!

Apologies for the commit, but I'm pushing on a lot of things simultaneously.
The main focus is usability and documentation, so here are notable things:

* Now directly injecting core and functions bits into the pyplate being parsed
  This means no more cfn_pyplates. prefix on everything, though pyplate users
  should still feel free to import whatever, from wherever they choose, to
  accomplish their goals
* So many docstrings! Coming in the next commit: Sphinx docs, with autodocs
  using htose docstrings to make useful docs
* Drastic changes caused a version bump. Welcome to 0.1.0!
* Added some tests to match the new functionality, more to come.
The docs! Still need examples...