Merge pull request #31 from perezsolerj/hydro-devel

Moved trajectory visualization from ROSInterface to new file.
Added Force Sensor using bullet collision reactions.
Modified dynamics module to use this force sensor as force input.
Merge branch 'hydro-devel' of https://github.com/uji-ros-pkg/underwater_simulation into hydro-devel
Adding ForceSensor missing files on last commit.
Removed robot_state_publisher source download from travis, no longer needed.
minor ForceSensor fixes:
- translation offset is no longer hardcoded
- Moved vehicle initial position so does not collide.
- Reset collision force on dynamics helping framerate  independence.
Added keyboard controller for teting dynamics.
remove tarball after download
Merge pull request #34 from srv/hydro-devel

remove tarball after download
Fixed ForceSensor was required in DTD, now is optional
Merge remote-tracking branch 'upstream/hydro-devel' into hydro-devel