Implement optional automatic file compression

[Septolum]

Add an option for files to be automatically compressed before being converted to qr (with possibly a check for if the file size is smaller when compressed, if not just use the raw)

[mofosyne]

Can't see anything wrong with that. A minor issue would be that you cannot easily decode a half decoded file if a single QR code is missed. At least without compression, you can see part of the data, especially if it is in plain text. Also you need to have a way to check if we are using compression or not, but that depends on how the compression is done. If we are using a datauri like system, we could make a schema like lzma: as the trigger word.