Adding polymorphic unit tests for enble_shared_from_this
Adding polymorphic unit tests for enble_shared_from_this

Should fix #47

abutcher-gh/cereal,arvidsson/cereal,stevehickman/cereal,lyager/cereal,vcatechnology/cereal,jonathan-beard/cereal,sschaetz/cereal,adasworks/cereal,stevehickman/cereal,syxolk/cereal,vcatechnology/cereal,arvidsson/cereal,JosephLaurino/cereal,JosephLaurino/cereal,jonathan-beard/cereal,fawkes74/cereal,heamon7/cereal,sschaetz/cereal,abutcher-gh/cereal,guker/cereal,adasworks/cereal,headupinclouds/cereal,guker/cereal,headupinclouds/cereal,syxolk/cereal,USCiLab/cereal,jkhoogland/cereal,RobertoMalatesta/cereal,USCiLab/cereal,jkhoogland/cereal,lyager/cereal,RobertoMalatesta/cereal,heamon7/cereal,fawkes74/cereal