[HowTo] RetroPie and OSMC: Retrosmc - Retrogaming on OSMC

@exobuzz
As the move to debian stretch broke RetroPie as libs are missing, would it be ok to have an exception in the installer script, that detects osmc and lets it run it anyway? There is a workaround we can implement in the retrosmc script that will make it start again.

Edit: Is there some timeframe for stretch support for Retropie already? In this case ot might be easier to just wait for now.