Commonly used messages in ROS. Includes messages for actions (actionlib_msgs), diagnostics (diagnostic_msgs), geometric primitives (geometry_msgs), robot navigation (nav_msgs), and common sensors (sensor_msgs), such as laser range finders, cameras, point clouds.
I noticed that this dependency was missing in sensor_msgs, which uses gtest. This is contrary to http://docs.ros.org/jade/api/catkin/html/howto/format1/gtest_configuration.html.
See also #85