Fix timer text display on certain display sizes

NEW look and timer formats including 10 Min Movement and Express Cardio

NEW timer formats including 30 Min Pilates, HIIT Pilates and 45/15 Sweat

New timer modes:
- 30 Minute Pilates
- HIIT Pilates
- 45/15 Sweat

Fix background audio mode

Support for iOS 15

- Support for iOS 13
- Increased timer accuracy over long periods of time
- Fixed background timer related issues

Added a visual back button, fixed background audio modes with music