Add 4 byte integer type

Cassandra currently lacks support for 4byte fixed size integer data type.

Java API Hector and C libcassandra likes to serialize integers as 4 bytes in network order. Problem is that you cant use cassandra-cli to manipulate stored rows. Compatibility with other applications using api following cassandra integer encoding standard is problematic too.

Because adding new datatype/validator is fairly simple I recommend to add int4 data type. Compatibility with hector is important because it is most used Java cassandra api and lot of applications are using it.

This problem was discussed several times already
http://comments.gmane.org/gmane.comp.db.hector.user/2125
https://issues.apache.org/jira/browse/CASSANDRA-2585

It would be nice to have compatibility with cassandra-cli and other applications without rewriting hector apps.