- modified CMakeLists.txt to support also MingW GNU c++ under Windows. - other improvements in MingW - Fixed a nasty bug in deallocation of smart pointers to vector of    btCollisionShape items in ChCollisionShape deletion, it caused crashes   when closing demos, in debug mode.
- modified CMakeLists.txt to support also MingW GNU c++ under Windows.
- other improvements in MingW
- Fixed a nasty bug in deallocation of smart pointers to vector of 
  btCollisionShape items in ChCollisionShape deletion, it caused crashes
  when closing demos, in debug mode.


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