Check Dejavu reenterability

[denis-stepanov]

Observations show that Dejavu in threading environment does not perform as well as expected. Possible effects to check:

1. check that audio input submitted to Dejavu is not distorted because of threading;
2. check that Dejavu itself is reenterable.

If no changes, the default sensitivity could be lowered from 10% to 5% - looks like at this level there are still no false positives.

[denis-stepanov]

1. check that audio input submitted to Dejavu is not distorted because of threading;

Dejavu code was temporarily modified to save inputs into files; slicing by 2-6 threads did not reveal any distortion. This is a very good result.

2. check that Dejavu itself is reenterable.

Study of Dejavu source code did not reveal particular issues with reenterability.

If no changes, the default sensitivity could be lowered from 10% to 5% - looks like at this level there are still no false positives.

Done. With this I am resolving.