fixed wrong download link in tutorial
fixed IPP related warnings
Merge pull request #2708 from StevenPuttemans:2.4
Merge pull request #2706 from ilya-lavrenov:ipp_2.4_warnings
add suggestion of feature 2619
Merge pull request #2717 from StevenPuttemans:2.4
Merge branch '2.4' of git://github.com/Itseez/opencv into 2.4