The models and meshes are not included. We will need
to find an alternate way to reintegrate these and use them.
* Add simulation/gz_msgs back, and build with Gradle.
* Add back in the frc simulation plugins for gazebo.
* Add a new shared library, halsim_gazebo.
This library will become the interface between the
HAL sim layer and gazebo.
* Preserve the first channel number used in created Encoders in the Sim MockData.
This allows us to use the DIO channel number to connect with simulated encoders.
* Have the HAL Simulator set the reverse direction on creation.
This enables a simulator to be aware of the direction.
* Add a drive_motor plugin.
This is a bit of a 'magic' motor, which allows us to build robot
models that drive in a more realistic fashion. It does this
by apply forces directly to the chassis, rather than relying on
the complex motion dynamics of a driven wheel.
This in turn allows the model to reduce wheel friction,
reducing scrub, and allowing for a more natural driving experience.
