message: Update README.md
  Made description more explicit as in
  So somebody who got compilation error and opening creates.io description can see simple solition for most widely used systems,
  e.q. it's called libopencv-dev on ubuntu, not opencv-dev
diff: @@ -27,6 +27,17 @@ use opencv::prelude::*;
  ### Linux
  +#### Arch Linux:
  +
  +OpenCV package in Arch is suitable for this.
  +
  +`pacman -S clang qt5-base opencv`
  +
  +#### Ubuntu:
  +
  +`sudo apt install libopencv-dev clang libclang-dev`
  +
  +#### Other Linux:
  You have several options of getting the OpenCV library:
  * install it from the repository, make sure to install `-dev` packages because they contain headers necessary
  