Silan cue-in/out analysis now moved to airtime_analyzer

* Added a new CuePointAnalyzer using silan (will remove silan stuff from pypo later)
* Makes silan analysis slightly more reliable for certain short files.
* Fixes CC-5961: Audio duration cutoff for WAVE files
* Added unit tests for the new analyzer and improved code coverage slightly
* Added unit tests for WAVE metadata extraction and an invalid WMA file