Add first version of Cassandra connector. This plugin is still in
development and is not yet bundled with the server. See the README
in the plugin source directory for details.
Support UDFs for internal plugins. This is not yet part of the SPI
and is a stopgap feature intended for advanced users. UDFs must be
implemented using the internal Presto APIs which often change
substantially between releases.
Fix Hive connector semaphore release bug.
Fix handling of non-splittable files without blocks.