Doc: Renamed and moved examples/qml/i18n to examples/qml/qml-i18n

-the generated HTML page conflicts with the i18n.html page from qtdoc.
-edited the content.

Task-number: QTBUG-32580
Change-Id: I32ded1913d9faecb95e28043983e957ccd0e8749
Reviewed-by: Martin Smith <martin.smith@digia.com>
Doc: Renamed accessibility example to "quick-accessibility".

-Generated HTML file name conflicted with accessibility group.

Task-number: QTBUG-32580
Change-Id: I5f5a4bb8134268c58105ea61d5ae3bbdd35c0d50
Reviewed-by: Martin Smith <martin.smith@digia.com>
Change post-increment/-decrement to not use a built-in.

Change-Id: I98af408db1e5d23e73a77d2614071bc998170f5e
Reviewed-by: Lars Knoll <lars.knoll@digia.com>