[issue #807] Added MBot model for gazebo simulator

[fqez]

This model has been tried with the default plugins of the taxis both motors and pose3d, which don't use physics.

[aitormf]

when I use the model obtain the following error:

constructor motors
-----------------constructor Pose3D
--Ice.Config=carMotors.cfg
GetName() Pose3D: mbot
[Info] loaded Ice.Config file: /usr/local/share/jderobot/conf/carMotors.cfg
Motors Endpoints > default -h 0.0.0.0 -p 9999:ws -h 0.0.0.0 -p 11002
easyice/loader.cpp:51: Ice::FileException:
file exception: couldn't open file
path: mbotPose3D.cfg

And model's name in gazebo is "mobt" instead of "mbot"

[fqez]

That's not a critic error because it needs its own plugins, so I can comment the pose3d plugin loading until there are several plugins for the MBot.