Load sdf

[Agustin Alba Chicar]

Load SDF file as a world plugin and try to get it working so all the arguments are taken from there.

[Agustin Alba Chicar]

@JChoclin I've got the following error message:

Warning [parser.cc:778] XML Element[rndf], child of element[world] not defined in SDF. Ignoring[rndf]. You may have an incorrect SDF file, or an sdformat version that doesn't support this element.

With the following world file:

<?xml version="1.0"?>
<sdf version="1.4">
  <world name="darpa">
    <include>
      <uri>model://ground_plane</uri>
    </include>
    <include>
      <uri>model://sun</uri>
    </include>
    <plugin name="dynamicrender" filename="libnrdf_gazebo_plugin.so"/>
    <rndf filepath="/home/gazebo/ws/rndf_gazebo_plugin/example/darpa.rndf" lanes="true" waypoints="true"/>      
  </world>
</sdf>

I think we need to define first our tags. Also, no standard output is provided through the world plugin. So it is difficult to debug what's going on. I've tested this on our repository and also on the bare example.

[Javier Iván Choclin]

Improvements on loading sdf file. refs #28

→ <<cset b97883d7e2a6>>

[Javier Iván Choclin]

Improved to get arguements from the sdf file. refs #28

→ <<cset f6f8448201e1>>

[Javier Iván Choclin]

SDF file loading working. refs #28

→ <<cset 407a20861a71>>

[Javier Iván Choclin]

README update and change a message. refs #28

→ <<cset 24e01ba59ee2>>

[Javier Iván Choclin]

Included message explaining how we parse the SDF file. refs #28

→ <<cset d82cdef19e2a>>