Recreate resource retriever behaviour by specifying the ROS_PACKAGE_PATH as environment variable.

[C++][Geom Parser] put default value to empty vector of string for user hint directories. If user's hints and ROS_PACKAGE_PATH empty, then throw error. The function that parse ROS_PACKAGE_PATH doesn't throw errors anymore

[C++][Geom parser] Removed boolean root_joint_added while parsing. Geom parser modified consequently to look for parent of link in pinocchio model  now instead of urdf::tree parent joint.

[C++][Pyhton][Geom parser] ROS_PACKAGE_PATHS directories are now added to the ones specified by user

[Python] Update methods and RobotWrapper to use buildGeom instead of buildModelAndGeom and to use a list of package dirs instead of one meshRootDir.If no package_dirs is given by the user, then it will call the C++ procedure that automatically parse the ROS_PACKAGE_PATH

[Python] Added method to convert a python List of string to a C++ vector of string. Warning: the type checking must be made by user before using this function

[C++][Python][Parser Geom] Parse automatically the ROS_PACKAGE_PATH environment variable if not clue is given by the user to where to search for meshes. Change the meshRootDir argument to a vector of strings (package directories). Updated Python consequently

Improve doc of Model+Data and add python bindings in Travis

Add CCRBA algorithm

Add ABA algorithm

Inertia.From{Ellipsoid,Cylinder,Box}

Rework center of mass algo + Python API