Add *.png explicitly to assets precompilation

    , so video...png can stay in vendor/..

Squashed commit of the following:

commit daf78954f7179c0889dcd106cd4fce6ac88c675f
Author: Thomas Schank <DrTom@schank.ch>
Date:   Thu Feb 20 12:11:17 2014 +0100

    Compiling all pngs

commit 6ed567e7c31bc3870f3b55f1e5c7182b6bbef05a
Author: Thomas Schank <DrTom@schank.ch>
Date:   Thu Feb 20 11:58:33 2014 +0100

    Add video-js.png explicitly to assets precompilation

    , so it can stay in vendor/..