title: QT 5.2.0 - Cannot add commands to previously defined target
body: <p>I have this problem while Building project: </p>
  
  <pre><code>17:49:24: Running steps for project SceneVisualizer...
  17:49:24: Configuration unchanged, skipping qmake step.
  17:49:24: Starting: "D:\Qt\Qt5.2.0\Tools\QtCreator\bin\jom.exe" 
      D:\Qt\Qt5.2.0\Tools\QtCreator\bin\jom.exe -f Makefile.Debug
  Cannot add commands to previously defined target debug\moc_previewwindow.cpp.
  Cannot add commands to previously defined target debug\moc_visualizerwindow.cpp.
  17:49:24: The process "D:\Qt\Qt5.2.0\Tools\QtCreator\bin\jom.exe" exited normally.
  17:49:24: Elapsed time: 00:00.
  </code></pre>
  
  <p>When i chose to run project from QT:</p>
  
  <pre><code>Starting D:\filipbp\Projekty, zdrojove kody\build-SceneVisualizer-Desktop_Qt_5_2_0_MSVC2010_32bit_OpenGL-Debug\debug\SceneVisualizer.exe...
  The program has unexpectedly finished.
  D:\filipbp\Projekty, zdrojove kody\build-SceneVisualizer-Desktop_Qt_5_2_0_MSVC2010_32bit_OpenGL-Debug\debug\SceneVisualizer.exe crashed
  </code></pre>
  
  <p>When I run .exe from outside, it starts correctly, but if I chose to load prepared scene, the program crashes.</p>
  
  <p>I don't know what to do with it, please help.</p>