Demessify - I am so sorry

@stoodder @jeregrine @Gregadeaux @mitchellhenke @nickgartmann 

Lots of changes. Created `StorkAPI` and `StorkDisc` to pull out as many operations as possible out of `Stork`. `Stork` now really only handles state, config, and notifications.

I believe most of these changes are internal. Usage should have stayed the same.

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To use, update Podfile to...
```
pod 'Stork', :git => 'https://github.com/StorkHQ/stork-ios.git', :branch => 'demessify'
```

and then run

```
pod install
```

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Tear this apart and ask any questions
did you mean kDefaultHoldingDirectory? (no s)