Redesign indexes on projections

1) MangetoDB Table structure was redesigned
2) Tenant's keyspace "user_" was added
3) system table "magnetodb"."table_info" added to store MagnetoDB Table info and
   statuses
4) Table CRUD operation redesigned to work with "magnetodb"."table_info" table
5) Item CRUD operation was redesigned to support Local Secondary Indexes
6) Cassandra >=2.0.6 cluster required for Cassandra support
7) Cassandra python driver sources was copied to MagnetoDB codebase because
   release of version 2.0 isn't exist

Implements: blueprint redesign-indexing

Change-Id: Ifda2f9a9e315d08c944732a4aa4bcc59cb3ca583
Merge "Redesign indexes on projections"