integrate support of std::shared_ptr in addition to boost::shared_ptr and perhaps other smart pointers implementing similar concepts #29
Description
currently the support of boost::shared_ptr islands code using std::shared_ptr. While in some cases the user can simply choose to use boost::shared_ptr over std::shared_ptr, this does not work on a pre-existing library whom chose to use std::shared_ptr.
It may also be worth considering older libraries out there who'm had chosen to implement their own smart ptr ( e.g. OpenSceneGraph, ITK/VTK) though I'm not sure they'll support 1:1 the same exact concepts shared_ptr does.