Implementing a demo project

@mgorbach 
Assigning this to you, we can discuss at the standup tomorrow.
Closes #1.

Demo project for RZVinyl outlining many of the core features.

#### Features Demonstrated
- Importing
- ActiveRecord extensions
   - Delete
   - Count
   - Fetch by attributes
   - Fetch by primary key
- "Scratch" context for editing

#### Features Not Demonstrated
- Creating a new object in-app
   - Requires lots of UI
- Direct query using AR extensions (not using fetched results controller)
   - No good use for it here, will document in README
They have a whole category on `NSManagedObjectContext` just for saving. Pretty convenient actually. But I wouldn't want to rip them off.