Padatious

- Add support for saving / loading models
- Handle apostrophes in a better way

Fix bug causing multiple entities to fail, especially when the entity contents contained a lot of words. Architecturally, `EntityEdge` no longer can detect the number of unknown words in an input.

The following features have been implemented:
- Version number (excluding patch level) is embedded in hash so that on version upgrades the cache is regenerated. For example, `0.2.1 -> 0.2.2` will not force regeneration, but `0.2.1 -> 0.3.0` will
- Support for parentheses expansion:


Will it (rain|pour) (today|tomorrow|)?

Will turn into:

Will it rain today?
Will it rain tomorrow?
Will it rain?
Will it pour today?
Will it pour tomorrow?
Will it pour?

Fixes a few critical bugs (thanks to the addition of unit tests), and adds a new `padatious.Container.add_intent` method.