add a VirtualRobot::Robot::clone function taking no parameter that just clones the robot (no renaming etc)

add overloads of SceneObject::getInertiaMatrix which transform the matrix into a different system (if the matrix was given at the com)

texture duplicate removal: using absolute path and filesize to determine if a texture is a duplicate

Improve hand closing movements: close all finger elements until joint limits reached or collision detected

improve error message for "only revolute joints supported" in bullet robots (now the node name is printed)

Time optimal trajectory

See merge request !17

add algorithm for calculating time-optimal trajectories with given velocity and acceleration constraints, which was developed by Humanoid Robotics Lab of Georgia Institiute of Technology