Lilypondtobandvideoconverter

Apart from minor bug fixes and refactorings two major changes have been done:

- The configuration file syntax has been simplified: it is no longer necessary to use a continuation marker "\\" for combining several physical lines into a logical line. Instead physical lines in the configuration file are collected up to an empty line or another definition line.
- It is possible to add a panning specification to the voice volume definitions. Panning is either done by the external mix command or by an internal pan algorithm that does standard balancing of stereo files.

Several minor changes have been done:
- added static typing tags for additional documentation of the code
- professionalized the processing and handling of configuration file data by a generic data type management
- tried to reduce the mandatory configuration variables as much as possible by providing reasonable default settings
- added a new logging file command line parameter (overriding the setting in the configuration file)
- set logging time resolution to 10ms (instead of 1s)
- renamed configuration variable _keepIntermediateFiles_ to _intermediateFilesAreKept_
- added several minor corrections in the processing variables (e.g. _tempLilypondFilePath_ now has placeholders for phase and voice name)
- ensured that the temporary MIDI file now uses the instruments from the configuration file
- made all temporary files go into directory given by configuration variable _intermediateFileDirectoryPath_ and allowed for a distinctive naming for different phases or voices
- corrected erroneous AAC processing by ffmpeg

Initial version of LilypondToBandVideoConverter