Ktrain

New:
- If no validation data is supplied to `images_from_array`, training data is split to generate validation data

Changed
- issue warning if Learner cannot save original weights
- `images_from_array` accepts labels in the form of integer class IDs

Fixed:
- fix pandas `SettingwithCopyWarning` from `images_from_csv`
- fixed issue with `return_proba=True` including class labels for multilabel image classification
- resolved issue with class labels not being set correctly in `images_from_array`
- lock to `cchardet==2.1.5` due to [this issue](https://stackoverflow.com/questions/60784527/ktrain-importerror-dll-load-failed-the-specified-module-could-not-be-found)
- fixed `y_from_data` from NumpyArrayIterators in image classification

New:
- N/A

Changed
- N/A

Fixed:
- fixed issue with MobileNet model due to typo and added MobileNet example notebook

New:
- N/A

Changed
- added `merge_tokens` and `return_proba` options to `NERPredictor.predict`

Fixed:
- N/A

New:
- N/A

Changed
- added `textutils` to `text` namespace and added note about `sent_tokenize` to sequence-tagging tutorial

Fixed:
- cast dependent variable to `tf.float32` instead of `tf.int64` for text regression problems using `transformers` library

New:
- N/A

Changed
- added `suggest` option to `core.Learner.lr_plot`

Fixed:
- set interactive mode for matplotlib so plots show automatically from Python console and PyCharm
- run prepare for NER sequence predictor to avoid matrix mismatch

New:
- N/A

Changed
- N/A

Fixed:
- ensure `text.eda.TopicModel.visualize_documents` works with `bokeh` v2.0.x