Curator API

Add Curator API (mix task).
Add Opaque Token for use with Guardian.

Version 0.2.0 - Ueberauth + Timeout Only

Supports Phoenix 1.3 Directory structure (and umbrella applications)

Curator has been rewritten to follow the patterns established in Guardian 1.0

Configuration is now done in the "implementation", basically a module that calls 'use Curator'. The various modules that were distinct Hex packages will be moved into this project (but extensions can still exist outside the main codebase). Once configured, this provides a way to hook into to curator life cycle and the router with less manual work. The various extensions will also include generators so it should be quicker to get an application running, while still providing the ability to customize some features.