DATAStack — 5.1.0

Added

/**
 Most of the time when saving a background context you want that it merges the saved changes with the main 
 context, but when you're performing partial savings, such as batch saves you don't want this to be the case.
 - parameter context: The block that contains the created background context.
 */
public func saveBackgroundContextWithoutMergingWithMainContext(context: NSManagedObjectContext) throws