Merge remote-tracking branch 'origin/2.4' into merge-2.4

Conflicts:
	modules/contrib/src/spinimages.cpp

doc/tutorials/introduction/linux_install/linux_install.rst

@@ -23,7 +23,7 @@ The packages can be installed using a terminal and the following commands or by
     .. code-block:: bash
 
        [compiler] sudo apt-get install build-essential
-       [required] sudo apt-get install cmake git libgtk2-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev
+       [required] sudo apt-get install cmake git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev
        [optional] sudo apt-get install python-dev python-numpy libtbb2 libtbb-dev libjpeg-dev libpng-dev libtiff-dev libjasper-dev libdc1394-22-dev
 
 Getting OpenCV Source Code

modules/contrib/src/spinimages.cpp

@@ -1190,9 +1190,9 @@ private:
 
 cv::TickMeter::TickMeter() { reset(); }
 int64 cv::TickMeter::getTimeTicks() const { return sumTime; }
-double cv::TickMeter::getTimeMicro() const { return (double)getTimeTicks()/getTickFrequency(); }
-double cv::TickMeter::getTimeMilli() const { return getTimeMicro()*1e-3; }
-double cv::TickMeter::getTimeSec()   const { return getTimeMilli()*1e-3; }
+double cv::TickMeter::getTimeSec()   const { return (double)getTimeTicks()/getTickFrequency(); }
+double cv::TickMeter::getTimeMilli() const { return getTimeSec()*1e3; }
+double cv::TickMeter::getTimeMicro() const { return getTimeMilli()*1e3; }
 int64 cv::TickMeter::getCounter() const { return counter; }
 void  cv::TickMeter::reset() {startTime = 0; sumTime = 0; counter = 0; }