Remove duplicates from use orocos variables

The `USE_OROCOS_*` variables currently contain a lot of duplicates. I added `list(REMOVE_DUPLICATES ...)` commands for each of them.

I am not sure if this works in all cases, as catkin uses an extra [list_append_unique](https://github.com/ros/catkin/blob/groovy-devel/cmake/list_append_unique.cmake) macro for INCLUDE_DIRS, LIBRARY_DIRS and LIBRARIES and they do not rely on `list(REMOVE_DUPLICATES ...)` (I assume due to issues with reordering).