App Restructuring

[joshhudnall]

Changes

• Added option to save to origin folder without asking
• Made options persistent using NSUserDefaults
• If file is dropped on icon while the app is not already open, app quits after the process is complete
• Moved warnings and errors to a tableview instead of an alert for easier reference and to not block the UI, removing a click from the UX process
• Moved declarations intended to be private into private categories
• Created a constants file referenced in Unretiner-Prefix.pch to keep keys standard across files

Known Issues

• The URL returned from the select destination folder dialog has to be checked twice to get rid of the number of path components, not sure why. There's probably a better way, but it's functional.

Notes

Some of the code is refactored by the nature of moving the Unretiner methods into the singleton class. This was necessary because the methods that handle file drops on the app icon are finished before the UnretinaViewController is instantiated. Other than that, I attempted to keep the same structure and style.

There was a method in AppDelegate.m called
- (void)appication:(NSApplication*)sender openFile:(NSString*)file
that I don't think was actually doing anything. I've corrected the naming and pointed it to the openFiles variant of the same method. (I'm more familiar with iOS than OSX development, so I'm not sure if keeping it is even necessary as the app was functioning as expected without it.)