removed obsolete headers from opencv.hpp, fixed 2 gcc warnings and bug in SVBackSubst().

samples/cpp/camshiftdemo.cpp

@@ -50,7 +50,6 @@ int main( int argc, char** argv )
     VideoCapture cap;
     Rect trackWindow;
     RotatedRect trackBox;
-    CvConnectedComp trackComp;
     int hsize = 16;
     float hranges[] = {0,180};
     const float* phranges = hranges;

samples/cpp/lkdemo.cpp

@@ -106,7 +106,7 @@ int main( int argc, char** argv )
             points[1].resize(k);
         }
 
-        if( addRemovePt && points[1].size() < MAX_COUNT )
+        if( addRemovePt && points[1].size() < (size_t)MAX_COUNT )
         {
             vector<Point2f> tmp;
             tmp.push_back(pt);