Improve Documentation

[Minor] Set lower position limit to -infinity, not +infinity

- remove leftidx package, not available in MathJbx
- replace `\leftidx{^` by `{}^{`
- fix param lists
- comment documentation of commented code
- replace `<i>` & `<li>` with `*i*` & `*li*`, that are valid in html & md

Python 3

[Python] Minor. Remove duplicate methods. minor rearrangement

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