NA-2045 Sharing connections between various instances of HecubaClientManager:

-After moving to datastax we can connect to multiple column family and key spaces using same session and cluster respectively.
-It is the recommended way of using the driver.
-This patch includes changes for cluster and session sharing between multiple HecubaClientManager instances.
Merge branch 'schema' of https://github.com/anschauhan/hecuba into schema

Conflicts:
	src/main/java/com/wizecommerce/hecuba/datastax/DataStaxBasedSessionObjectFactory.java
	src/main/java/com/wizecommerce/hecuba/datastax/SessionCachingKey.java