Update ProgressForm
Fix extracting GUI...

- Do extracting in background if using GUI
- Fix the "Cancel" button
- Show progress in title
Add CustomPath/CustomPaths classes...

Will be used to define custom quick extract paths.
Improve quick extract...

- Remove predefined paths (Fallout 3/NV, Skyrim, Oblivion)
- Add the ability to add custom quick extract paths
- Rename CustomPath to QuickExtractPath
Rename UseFolderName to UseFolderPath