Adapt dls2 to read a generic robot library

[MMarcus95]

A generic gluecode library is created, and the initialization is based on robot name

[MMarcus95]

When getting a new robot urdf:

add gazebo plugins for blind state, desired commands, base state

  <gazebo>
    <plugin filename="/usr/lib/dls2/hardwares/gazebo_plugins/libgazebo_hw_sim.so" name="gazebo_hw_sim"/>
    <plugin filename="/usr/lib/dls2/hardwares/gazebo_plugins/libgazebo_base_state.so" name="gazebo_base_state"/>
  </gazebo>

add fake sensor to load base_state plugin

  <gazebo reference="base_link">
    <sensor name="base_state" type="imu">
      <always_on>1</always_on>
      <update_rate>500</update_rate>
    </sensor>
  </gazebo>

add gazebo plugins for imu, remember to change the reference to the imu link name

    <gazebo reference="imu_link">
    <gravity>true</gravity>
    <sensor name="imu_sensor" type="imu">
      <always_on>true</always_on>
      <update_rate>1000</update_rate>
      <visualize>true</visualize>
      <topic>__default_topic__</topic>
      <plugin filename="/usr/lib/dls2/hardwares/gazebo_plugins/libgazebo_imu.so" name="trunk_imu_plugin">
        <updateRate>0.0</updateRate>
      </plugin>
      <pose>0 0 0 0 0 0</pose>
    </sensor>
  </gazebo>

add contact sensors if there are not there. The name has to be <foot_link_name>_contact. E.g., for left front foot

  <gazebo reference="FL_foot">
    <maxVel>1.0</maxVel>
    <maxContacts>1</maxContacts>
    <sensor name="FL_foot_contact" type="contact">
      <always_on>true</always_on>
      <update_rate>250.0</update_rate>
      <contact>
        <collision>FL_calf_fixed_joint_lump__FL_foot_collision_4</collision>
      </contact>
    </sensor>
    <material>Gazebo/Black</material>
  </gazebo>