add ur_description, fix #7

See merge request !13

from https://github.com/ros-industrial/universal_robot/tree/kinetic-devel/ur_description

some models don't have robot parameters, fix #13

See merge request !12

to comply with other packages

Added solo robot + fixed bug in the unit-test

See merge request gepetto/example-robot-data!11

to ease robotpkg packaging

s.t. Pinocchio can depend on the data, and we can provide simultaneously
several python versions

Added the loading function for talos legs + removed an path append inside display

See merge request gepetto/example-robot-data!10

Topic/end effector srdf

See merge request !9