Update defaultLocalStoreUrl to use defaultStoreName

`[MagicalRecord setupCoreDataStack]` uses `[MagicalRecord defaultStoreName]`
While the NSPersistentStore category is using the old constant.

For example, when kCFBundleNameKey exists.
`[MagicalRecord setupCoreDataStack]` creates the database at {kCFBundleNameKey}.sqlite
but `[NSPersistentStore MR_defaultLocalStoreUrl]` returns the old fallback file name `CoreDataStore.sqlite`

As I can see some tests are in *Needs porting*, what tests do you prefer?