New features:
- Manually add workouts (#53)
- Dark Mode (#48)

Improvements:
- Altitude correction
- Detect bluetooth headsets (#51)
- Show recording on lock screen (#45)
- OpenStreetMap attribution in the record screen (#52)

Bug-Fixes:
- Wrong speed values after GPS-signal was lost for some time (#47)

Localisation:
- update Dutch thanks to albertheres and didierm (#57, #58)
- update Hungarian thanks to urbalazs (#59)