Helpers to group objects by date + unit tests
Make sectionDictionaryFromArray more generic, moved to NSDictionary+SDExtensions
Return NSDictionary copy instead of dictionaryWithDictionary
Return NSDictionary copy instead of dictionaryWithDictionary (for real this time)
Merge pull request #82 from walmartlabs-wmusiphone/master

Helpers to group objects by date + unit tests