Handle recent version of boost >= 1.67.0

Under OSX, ctest is not reading the DYLD_LIBRARY_PATH of the current terminal.
This commit forces the correct export of DYLD_LIBRARY_PATH.

[Python] Fix RobotWrapper initDisplay and q0

[unittest] [Joint Composite] verify inertia update for calc_aba

  Now:
    - initDisplay just create a window and a scene which is automatically
  added to the window
    - loadDisplayModel create a group node for the robot and load visual
  geometries

Topic/aba

Topic/joint composite

Related to #456

Fix TYPEDEF for GNUC 442

Use ROMEO description as model

Handle XML stream inside URDF parsers

Add derivative of the difference operation.