Hyperactive

- new API that creates model by function and search space by dict
- enables more flexible usage (e.g. free use of framework, ensembles, nn-structure)
- 100% test coverage

- performance fixes for bayesian optimization and parallel tempering
- better default parameter for most optimizers
- better implementation for metrics
- add support for catboost
- integration of meta-learn code into hyperactive
- cleanup to avoid similar code

- k-fold-cross validation works with keras models
- a cv of < 1 trains the model on a fraction of the training data and tests on the rest
- better testing and code-coverage
- fix of score and predict method

- improvement of optimizer class structure
- lower memory usage
- add testing of optimization process
- a lot of clean up und several bug fixes (mostly parallel tempering)

- improved scatter initialization
- remove small bug in random seed
- add basic test

- add tabu search
- add parallel tempering
- add bayesian optimization