Reset BPM value if results of automatic analysis are ambiguous

[stengerh]

The BPM value for a track should be reset if the results of the automatic analysis are ambiguous. Ambiguouity should be detected based on the number or range of candidate BPM values. This behaviour should be controlled by configuration options.

Suggested by Z4g5r.

[stengerh]

I think this feature needs clarification, in particular regarding which criteria are useful to detect ambiguous results.