Update DS documentation images and check the contents

There are quite a lot text that is directed to developer and that makes you think who is the target user, especially in the beginning of the documentation. Would it be possible to have section for Designer and Developers?

Now, for example User interface section should mention which parts are important for Design studio user (designer) and also mention that parts 2-5 are for developing purposes and designer does not necessary have to work with kits, debug or classes and functions.

Other examples:
“Qt Design Studio caters not only to developers who are used to using the mouse, but also to developers who are more comfortable with the keyboard. A wide range of keyboard and navigation shortcuts are available to help speed up the process of developing your application.”

“If you receive a freely scalable icon in the SVG format from an UI designer, you can export it to several images of different sizes to create a set of pixmaps. You can then use QIcon::addPixmap() to add the pixmaps to icons in different modes and states.”

There are also some old images, for example in layouts.