This patch replaces the old Qt logo with the new, flatter one.

The PNGs were optimized via: optipng  -o7 -strip "all"

Task-number: QTBUG-41685
Change-Id: I51983a45144373bf7aee31a32990ecbb2582f488
Reviewed-by: Robert Loehning <robert.loehning@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

Updated those .qdoc files to refer to the new relative examples
emplacement. Images and snippets to be moved later.

Also grouped all widgets related examples under widgets.

Change-Id: Ib29696e2d8948524537f53e8dda88f9ee26a597f
Reviewed-by: J-P Nurmi <j-p.nurmi@nokia.com>

This is the beginning of revision history for this module. If you
want to look at revision history older than this, please refer to the
Qt Git wiki for how to use Git history grafting. At the time of
writing, this wiki is located here:

http://qt.gitorious.org/qt/pages/GitIntroductionWithQt

If you have already performed the grafting and you don't see any
history beyond this commit, try running "git log" with the "--follow"
argument.

Branched from the monolithic repo, Qt master branch, at commit
896db169ea224deb96c59ce8af800d019de63f12