* Add a TF in-graph tokenizer for BERT
* Add from_pretrained
* Add proper truncation, option handling to match other tokenizers
* Add proper imports and guards
* Add test, fix all the bugs exposed by said test
* Fix truncation of paired texts in graph mode, more test updates
* Small fixes, add a (very careful) test for savedmodel
* Add tensorflow-text dependency, make fixup
* Update documentation
* Update documentation
* make fixup
* Slight changes to tests
* Add some docstring examples
* Update tests
* Update tests and add proper lowercasing/normalization
* make fixup
* Add docstring for padding!
* Mark slow tests
* make fixup
* Fall back to BertTokenizerFast if BertTokenizer is unavailable
* Fall back to BertTokenizerFast if BertTokenizer is unavailable
* make fixup
* Properly handle tensorflow-text dummies
