fix typo in linux tutorial
fixed calculation method of "cv::TickMeter"
Merge pull request #2818 from StevenPuttemans:fix_linux_tutorial
Merge pull request #2834 from atinfinity:pullreq/140606-TickMeter-2.4
Merge remote-tracking branch 'origin/2.4' into merge-2.4

Conflicts:
	modules/contrib/src/spinimages.cpp
Merge pull request #2841 from SpecLad:merge-2.4