Features
- Added support for table of contents (CTOC). Resolved with input from pull request 2, added by @szeidner.
- Added support for picture and url fields in chapter frames (CHAP). Resolved with input from pull request 2, added by @szeidner.
- Enabled previously commented out support for unsync lyrics/transcription frames (USLT). Resolved with input from pull request 3, added by @theckr96.
Bug fixes
- Fixed incorrect parsing of tag size field. Resolves issue 1, reported by @VirtualAstronaut.