wip #300 - Redesigned Java API, some refactorings
wip #300 - Moved Java API class to japi subpackage, renamed CassandraJavaRow to CassandraRow under japi, japi.CassandraRow is now a regular class; extracted common portion of CassandraRow to AbstractRow; added tests for new CassandraRow class
wip #300 - renamed columnCount -> requiredColumns and consecutiveColumns -> consumedColumns in RowReader
wip #300 - renamed toCassandra -> writerBuilder, save -> saveToCassandra, SaveToCassandraOptions -> WriterBuilder, deprecated old way of saving data to Cassandra
Merge pull request #340 from datastax/wip-300

wip #300 - Redesigned Java API, some refactorings