add diffdrive_gazebo_plugin to rosinstall (required by uos_tools)
remove urdf_tools from rosinstall

* not required any more (functionality now provided by urdf_parser_py)
* doesn't compile
* SVN URL was outdated
remove tabletop_collision_map_processing from rosinstall

* doesn't compile
* outdated anyway (moved to https://github.com/ros-interactive-manipulation/pr2_object_manipulation)
Merge pull request #3 from mintar/fix_rosbuild_rosinstall

update rosbuild rosinstall