hide getSampleOf

- shouldUse getSubSample method
takes whole data set if sampling size larger than sample itself
removed feature definition.
correcting logic, selecting smaller one
removed keep functionality
simplified Cursor internals

- optimized cursor calculation logic
added progress bar over feature extraction, e.g. over single user
fixing broken tests
fixed rest of the tests.
adding progress bar over user feature extraction
simplified sampling logic
adding parallel processing option to PredictionsAndValidations
removed faulty parameterization of time distance

- there is no use case for moving history window backward
version bump
removed obsolete plotting tools
mixture as argument is now list of mixtures

- performance improvement
version bumb