wheezy-stage2: link to official documentation for config.txt
wheezy-stage4-lxde{-edu}: install epiphany and sonicpi2
wheezy-stage4-lxde-edu: add sonic-pi and minecraft-pi desktop icons
wheezy-stage3: install dosfstools
wheezy-stage4-lxde: ensure gstreamer deps are installed for epiphany
wheezy-stage4-lxde-edu: ensure ruby is marked manually installed
wheezy-stage4-lxde-edu: sonic pi 2 final doesn't include ruby