Reviewed DateFormatter used for date conversion

Reviewed how the DateFormatter is created to follow Apple's guidelines and demo implementation provided in [this documentation](https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/DataFormatting/Articles/dfDateFormatting10_4.html).

IMO, it makes more sense not to consider user locale since we generally are parsing dates from a backend API, not user entered data. If we don't do it this way, it seems the dates will be converted using local settings, such as non-Gregorian calendar, AM/PM preferences, etc.