BPE tokenizer (#389)

Add more test cases.

Co-authored-by: jessechancy <[email protected]>

add merge file

Make cache a tf module

Delete testdata

address comments

address comments

fix docstring

fix docstring

Author: chenmoneygithub

keras_nlp/tokenizers/__init__.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from keras_nlp.tokenizers.byte_pair_tokenizer import BytePairTokenizer
 from keras_nlp.tokenizers.byte_tokenizer import ByteTokenizer
 from keras_nlp.tokenizers.sentence_piece_tokenizer import SentencePieceTokenizer
 from keras_nlp.tokenizers.tokenizer import Tokenizer