add note to CHANGELOG about 2ndary indexing support
add note to CHANGELOG about 2ndary indexing support

rightscale/cassandra,stipple/cassandra_new,cassandra-rb/cassandra,stipple/cassandra_new,stipple/cassandra_new,stipple/cassandra_new,cassandra-rb/cassandra,rightscale/cassandra,cassandra-rb/cassandra,cassandra-rb/cassandra,rightscale/cassandra