Added eigen_conversion.hpp providing conversion from and to JSON for Modern C++

See merge request Simox/simox!32

* modernize-shrink-to-fit
* modernize-use-nullptr
* modernize-use-equals-default
* modernize-use-equals-delete
* modernize-unary-static-assert
* modernize-use-bool-literals
* modernize-replace-random-shuffle

    modernize-avoid-bind
    modernize-deprecated-headers
    modernize-redundant-void-arg
    modernize-replace-auto-ptr

by using CollisionChecker from CollisionModel in RobotNodeFactories
and avoiding unnecessary cloning of CollisionModel while attaching new node