Missing points in the technical documentation

[Rafiot]

HOWTO

• change/update the extension we would like to (force) accept
• modify the mime-types associated with an extension that are not known but still we consider reliable
• maybe have a more intuitive way to put these lines in a more human readable configuration file (instead of directly in the scripts code)
• eventually help me understand once modified these settings how to rebuild/prepare a new binary image to dump through dd onty the SDcard