Learner performances improvements (fair similarity, duplicate tokens
removal)
Conflicts:
	src/main/java/com/jaeksoft/searchlib/index/IndexConfig.java
	src/main/java/com/jaeksoft/searchlib/index/IndexSingle.java
Leaner support additional customs fields
Add stopwords on NamedEntityExtraction
Include modification date and length in replication (incremental
replication)
Incremental replication
Merge pull request #233 from emmanuel-keller/master

Bug fixes and improvements