More work into CUE file support.

- Tons of bug fixes in CueFileLoader; now loading CUE files
successfully, not missing much to have full CUE file support.
- Updated UpdateLibraryService to load audio files related to CUE files.
Still a bit buggy because the whole audio files are also imported (not
only the audio file pieces split by the CUE file).
- Added SelectFilePathsRelatedToCueFiles method to database facade.
- Updated database script to support CUE file paths, start/end positions
within an audio file