Fix for issue #70: running tests without first building fails

This uses the `DEPENDENCIES` argument added in `roslaunch` v1.9.55 to declare dependencies on the targets used in the roslaunch tests.

Tested on Hydro.

Commits updating the support packages in `fanuc_experimental` with the same changes will follow after acceptance of this PR.

Yes, this will break once project prefixes are added to `industrial_robot_client`, but I didn't see any other way.

I first tried using `catkin_EXPORTED_TARGETS`, but that didn't work. I'll have to check my notes to see whether it was because executable targets are not added to the exported targets, or because `industrial_robot_client` does things slightly different from 'normal' (the whole `_bswap` thing).

Note though: even if the target is renamed, the tests will work, just not if a user calls `run_tests_fanuc_driver` without building the workspace first. This is all just convenience. I figured prefixing the targets in `industrial_robot_client` (and `simple_message`) would not be something I'd miss, so I can update this as soon as necessary.