Remove unneeded dependency on pcl_ros

pcl_ros hasn't been released yet into indigo. I asked @wjwwood about
its status, and he pointed out that our dependency on pcl_ros
probably isn't necessary. Lo and behold, we removed it from the
header files, package.xml and CMakeLists.txt and gazebo_plugins
still compiles.
Fix repo names in package.xml's
Merge pull request #203 from jonbinney/groovy-repos

Fix repo names in package.xmls (groovy-devel branch)