Sonus

- Included author and title in invalid character replacement for file paths (Fixes 5)

- Replace invalid chars in Title (Fixes 5 )

**Fixed**:
- Added more invalid character replacements for filenames

**New**
- Added option to offset (`-O, --offset`) built-in chapter markers
- Examples: `--offset +5`, `--offset 10`, `--offset -10`

**New**
- Added `-f, --ffmpeg-debug` switch for easier troubleshooting

**Fixes**
- Fixed crash when track start and end timestamps are the same (1)
- Fixed missing debug message when using `-d, --download`

**Additions**
- Added new `--generic` option for chapter filenames (Chapter 1.mp3, Chapter 2.mp3, etc.)

**Fixes**
- Append filename with track number to prevent overwriting chapters with same name
- Replace certain invalid characters in filenames (`! ? : ,`)