Add virtual destructor for abstract IPostProcessingRenderCallback
Add virtual destructor for abstract IPostProcessingRenderCallback

Fixes clang warning, -Wdelete-non-virtual-dtor

dariomangoni/chrono,tjolsen/chrono,rserban/chrono,PedroTrujilloV/chrono,hsu/chrono,andrewseidl/chrono,hsu/chrono,andrewseidl/chrono,hsu/chrono,amelmquist/chrono,jcmadsen/chrono,projectchrono/chrono,dariomangoni/chrono,projectchrono/chrono,dariomangoni/chrono,jcmadsen/chrono,projectchrono/chrono,amelmquist/chrono,rserban/chrono,amelmquist/chrono,Milad-Rakhsha/chrono,dariomangoni/chrono,jcmadsen/chrono,PedroTrujilloV/chrono,PedroTrujilloV/chrono,hsu/chrono,armanpazouki/chrono,Milad-Rakhsha/chrono,projectchrono/chrono,rserban/chrono,PedroTrujilloV/chrono,dariomangoni/chrono,Bryan-Peterson/chrono,jcmadsen/chrono,jcmadsen/chrono,Bryan-Peterson/chrono,andrewseidl/chrono,andrewseidl/chrono,Milad-Rakhsha/chrono,Bryan-Peterson/chrono,amelmquist/chrono,armanpazouki/chrono,armanpazouki/chrono,Bryan-Peterson/chrono,amelmquist/chrono,Bryan-Peterson/chrono,tjolsen/chrono,dariomangoni/chrono,rserban/chrono,PedroTrujilloV/chrono,rserban/chrono,hsu/chrono,tjolsen/chrono,Milad-Rakhsha/chrono,rserban/chrono,tjolsen/chrono,projectchrono/chrono,armanpazouki/chrono,andrewseidl/chrono,armanpazouki/chrono,rserban/chrono,projectchrono/chrono,amelmquist/chrono,Milad-Rakhsha/chrono,tjolsen/chrono,jcmadsen/chrono,Milad-Rakhsha/chrono,jcmadsen/chrono,armanpazouki/chrono