Test client on mobile devices (smartphones, tables)

[nuest]

The JS client was very well tested on tablets and smartphones. We should make sure that sensorweby also works well on client. This would also be a good time to re-check that the minified version of shiny.js works as expected to minimize traffic. We could even go to an Open Device Lab, e.g. in Osnabrück (http://odl-os.infomantis.de/odl-os.html) to test the application on many different devices.