Affected packages:
- wip/pal-hardware-gazebo-melodic
- wip/pal-hardware-gazebo
- wip/play-motion
- wip/pal-transmissions
- wip/prf-ros-controllers
- wip/talos-dev
- wip/pal-hardware-interfaces
- wip/prf-teleop-tools
- wip/py-roscontrol-sot
- wip/prf-gazebo-ros-pkgs-melodic
- wip/prf-gazebo-ros-pkgs

Merge branch 'half_differential_effort' into 'erbium-devel' Half differential effort See merge request control/pal_transmissions!2
fixed sign in head transmission
fixing half differential effort
Merge remote-tracking branch 'origin/license-refactor' into erbium-devel
Update PAL licenses

[wip/pal-transmissions] Add chaining of the environment to make openrobots having the highest priority.