Replace checks for `entityName` on NSManagedObject subclasses with `nameOfEntity`

`entityName` is declared on NSObject and was causing validation warnings when submitting to the App Stores.
Remove the shorthand entity name methods entirely
Make the `nameOfEntity` class method part of a protocol, not an interface
Revert to `MR_entityName` for the time being

There's more information at http://rentzsch.tumblr.com/post/82453434093/apple-claims-mogenerators-methods
Add synchronous save methods that return a success state and optional NSError

Closes #299
Closes #685
Don't dispatch save completion blocks to the main thread

This was causing UI pauses and unnecessarily blocking the main thread for people who didn't want that.

Closes #425
Save completion handlers no longer dispatch to the main thread by default. Update tests to reflect this.
Entity attribute names must begin with a lowercase letter — update the documentation to reflect this
Use the formal documentation warning parameter in Xcode's project settings
Fix the logging so that it shows all log calls below the currently set value as well
Add documentation for NSEntityDescription+MagicalDataImport.h
Add protocol for MOGenerator methods
Move NSArray+MagicalRecord to the Foundation directory
Who likes documentation? This guy!
Rename the data import helper functions to follow Apple's function naming guidelines
Rename category "MagicalRecord_DataImport" to "MagicalRecordDataImport"

I'm preparing for some auto generated header documentation, and the old
category name was a bit ugly.
Latest Expecta
Fix the iOS color from string function
"-ObjC" is invalid unless we're building a dynamic library
88.4% documented