Fixes for GCC C++11 compilation.
Fixes for GCC C++11 compilation.

This time, related to the fact that stringstream copy constructors are 'deleted' in C++11

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