Add update mechanism for the scripts on the sd-card

[florian-asche]

Add a update system that updates the picompose and all the other scripts that are build into the system.

[florian-asche]

My initial idea is that i move all files into a folder where a update scripts downloads new one from the site. There is also a update script that run when update is triggered.
This way i can also fix issues when needed. Question is, if i update one version after the other or jump from 1.0,0 to 10.0.0?