title: Qt Error: cannot open include file: 'opencv2/core/core.hpp' no such file or directory
body: <p>I want to build an opencv project using Qt 5.1_VS2010. I have included the path for opencv include files. But when I run the code, I get the error that specific .hpp file does not exist! I have checked in the directory and it actually exists there! another point that when I was trying to include it in my main c++ file, the auto completion guide actually helped me complete the whole path! so it means the directory and the header file was already recognized! anyway, part of my .pro file that includes the path is like this:</p>
  
  <p>INCLUDEPATH += "C:/opencv/build/include"</p>