fix __main__

python/example_robot_data/__main__.py

 from argparse import ArgumentParser
 
+import eigenpy
+
 from . import robots_loader
 
+eigenpy.switchToNumpyMatrix()
+
 ROBOTS = [
     'anymal', 'anymal_kinova', 'hyq', 'solo', 'solo12', 'talos', 'talos_arm', 'talos_legs', 'kinova', 'tiago',
     'tiago_no_hand', 'icub', 'ur5', 'romeo', 'hector', 'double_pendulum'