Doc: tutorial for developing an Android app

This tutorial explains how to create an app
that uses Qt Sensors QML module to move an
SVG image based on the changing accelerometer
values.

Change-Id: Id4d9c8b389c5b8ebb330c6dba2dee783a475ba17
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@digia.com>