Basic doxygen documentation support

- updated existing Doxyfile.in
- added corresponding cmake instructions
- added some specific files (layout, icon)
- clean existing doxygen warnings

Conflicts:
	CMakeLists.txt
	doc/CMakeLists.txt
	modules/core/include/opencv2/core.hpp
	modules/core/include/opencv2/core/base.hpp
	modules/core/include/opencv2/core/cuda.inl.hpp
	modules/core/include/opencv2/core/mat.hpp
	modules/core/include/opencv2/core/matx.hpp
	modules/core/include/opencv2/core/types.hpp
	modules/flann/include/opencv2/flann/lsh_table.h
	modules/imgproc/include/opencv2/imgproc.hpp

modules/video/include/opencv2/video/background_segm.hpp

@@ -218,6 +218,7 @@ public:
      * model.
      * @param image Input image
      * @param fgmask Output mask image representing foreground and background pixels
+     * @param learningRate Determines how quickly features are "forgotten" from histograms
      */
     virtual void operator()(InputArray image, OutputArray fgmask, double learningRate=-1.0);
 

modules/video/include/opencv2/video/tracking.hpp

@@ -258,7 +258,7 @@ CV_EXPORTS_W int meanShift( InputArray probImage, CV_OUT CV_IN_OUT Rect& window,
 /*!
  Kalman filter.
 
- The class implements standard Kalman filter \url{http://en.wikipedia.org/wiki/Kalman_filter}.
+ The class implements standard Kalman filter http://en.wikipedia.org/wiki/Kalman_filter.
  However, you can modify KalmanFilter::transitionMatrix, KalmanFilter::controlMatrix and
  KalmanFilter::measurementMatrix to get the extended Kalman filter functionality.
 */