renamed Console#flushHistory to more generic #shutdown
tried to shutdown reader but it breaks the shutdown hook, commented it out
specific help messages for each client method. Reverted existing logic that required a single help for all methods with same name in different clients.
Added help for delete
renamed query to queryBuilder as in other request builders
added help for delete by query
renamed query to queryBuilder as in other request builders

Conflicts:
	src/main/java/org/elasticsearch/shell/client/builders/core/ExplainRequestBuilder.java
fixed mistakes
modified structured
added help for explain
added help for get api
added help for index api
added help for multi get api