Cleaning up various bits of the code

Including:

- Removal of unnecessary date extensions methods. Explicit casting fixes
the problem.
- Removal of unnecessary new NSNumber()s. Explicit/implicit casting is
chosen instead.
- Changed names of some badly named variables
- Fixed some missed nested generics. We created the data classes, but
forgot to carry them across to the view.

And a few other stylistic changes. No change to functionality.