Timbre: Cut, Join, Convert mp3

1/8/2018

Minor changes:
- Added option to see file path in Audio picker

Bugs fixed:
- When trying to cancel an ongoing task, Timbre would sometimes crash. No more!
- Fixed a bug where Timbre couldn't pick some video files
- In some cases, video files were showing up in audio picker
- Sometimes the task notification would get stuck
- When a task fails, Timbre now automatically deletes any corrupt output files
- Ads will no longer play any sound