API for data only replication #685.

Conflicts:
	src/main/java/com/jaeksoft/searchlib/Client.java
	src/main/java/com/jaeksoft/searchlib/index/IndexLucene.java
	src/main/java/com/jaeksoft/searchlib/index/WriterInterface.java
	src/main/java/com/jaeksoft/searchlib/webservice/document/DocumentImpl.java