control cassandra-client side timeouts in catalog/cassandra.config file

While using large column families we were facing client side timeout after planning. Increasing the client side socket timeout for the Datastax driver helped us out. To use this one the following new config params have been introduced into the cassandra catalog config:
cassandra.client-read-timeout, which can be used to set the socket read timeout in ms. Be aware that this is on a per host basis, i.e. the whole thing times out after #(hosts)*timeout
cassandra.client-connect-timeout, which can be used accordingly to set the connection timeout.
PS: i have signed the facebook code agreement stuff