gazebo_ros: also support gazebo instead of gazebo_ros as package name for plugin_path, gazebo_model_path or gazebo_media_path exports
gazebo_ros: added deprecated warning for packages that use gazebo as
package name for exported paths
Merge pull request #34 from meyerj/support_gazebo_package_name_for_plugins_patch

also support gazebo instead of gazebo_ros for package exports