Initial move toward MVVM.
Added FRPGalleryViewModel.
Refactord RACCommand for updating collection view.
Initial work on FRPFullSizePhotoViewModel.
Merge branch 'master' into mvvm

Conflicts:
	Podfile.lock
Removed RACCommand from view model.
Completed FRPFullSizePhotoViewModel.
Added FRPPhotoViewModel.
Fixed a problem with FRPFullSizePhotoViewModel.
Abstracted photo name into view model.
Removed dead code.
Added FRPLoginViewModel.
Fixed a problem where I forgot to instantiate the login view model.
Added photo detail view model.
Removed unnecessary header imports.
removed readwrite property from view model.
Fixed up photo view controller dismissing progress HUD early.
Broke reference cycle in FRPLoginViewModel.
Further abstracted initial photo model.
Removed more imports.