Flaubert auto tokenizer + tests

cc @julien-c

src/transformers/tokenization_auto.py

@@ -25,6 +25,7 @@ from .configuration_auto import (
     CamembertConfig,
     CTRLConfig,
     DistilBertConfig,
+    FlaubertConfig,
     GPT2Config,
     OpenAIGPTConfig,
     RobertaConfig,
@@ -41,6 +42,7 @@ from .tokenization_bert_japanese import BertJapaneseTokenizer
 from .tokenization_camembert import CamembertTokenizer
 from .tokenization_ctrl import CTRLTokenizer
 from .tokenization_distilbert import DistilBertTokenizer
+from .tokenization_flaubert import FlaubertTokenizer
 from .tokenization_gpt2 import GPT2Tokenizer
 from .tokenization_openai import OpenAIGPTTokenizer
 from .tokenization_roberta import RobertaTokenizer
@@ -67,6 +69,7 @@ TOKENIZER_MAPPING = OrderedDict(
         (GPT2Config, GPT2Tokenizer),
         (TransfoXLConfig, TransfoXLTokenizer),
         (XLNetConfig, XLNetTokenizer),
+        (FlaubertConfig, FlaubertTokenizer),
         (XLMConfig, XLMTokenizer),
         (CTRLConfig, CTRLTokenizer),
     ]