Violin pitch extraction and few improvements

[genisplaja]

In this PR we:

• Fix few minor problems
• Add the option to pass kwargs to the compiam.load_model() function
• Add the violin pitch tracking model courtesy of @venkatKrishnan86 (original repo is here).

[genisplaja]

If @venkatKrishnan86 you could also please take a look it would be amazing :) Thanks!