Purely syntactic changes to move_base/launch

Because I'm allergic to working with inconsistent files.
Since *any* tag supports `if`, no need to dup nodes.
Moved `move_base` to the main machine.

Obstacle handling with the chest xtion still run on the chest xtion's pc.
Renamed config.launch to obstacles.launch
Merge pull request #14 from lucasb-eyer/hydro-devel

Always run `move_base` on the main pc.