Additional Cassandra GORM implementation leveraging Spring Data Cassandra

Added to implementation leveraging work done in Spring Data Cassandra
https://github.com/spring-projects/spring-data-cassandra

TCK pass rate 193/220, with the remaining 27 skipped as associations are not yet implemented and some features (for e.g OR) not available in Cassandra.
 Features added include:
- non UUID and composite (partition, clustering) primary key support
- common types persistence including enums, lists, sets and maps, timeuuids, with conversions to/from various data types
- additional querying using dynamic methods and criteria for conjunctions, projections, counts, order bys, in list, range, limits, allowFiltering
- optimistic locking based on Cassandra's IF clause
- schema creation on startup