[release] 0.13.0 🎉

[eonu]

Major changes

• Switch from TravisCI to CircleCI. (#218)
• Add datasets.load_random_sequences for generating an arbitrarily sized dataset of sequences. (#216)
• Remove DeepGRU and classifier.rnn module. (#215)
• Add sequentia.datasets module. (#214)
• Added return_scores argument to KNNClassifier.predict() to return class scores. (#213)
• Return self in fit() functions. (#213)
• Update to hmmlearn v0.2.7. (#201)
• Update HMMClassifier structure to match KNNClassifier. (#200)
• Remove 'uniform' KNNClassifier weighting option. (#192)
• Fix major KNNClassifier label scoring bug - thanks @manisci. (#187)

Minor changes

• Update CONTRIBUTING.md CI instructions. (#219)
• Update HMM tests to use datasets module. (#217)
• Add tslearn as a core dependency. (#216)
• Remove torchaudio, torchvision and torchfsdd dependencies. (#214)
• Add playable audio to notebooks via play_audio helper. (#214)
• Update README.md and documentation. (#202)
• Add Jinja2 dependency for RTD. (#188)