Use local QR-Code generation instead of external service.

[sebsauvage]

Using a php lib or a js-lib.
(php lib would be better, this would avoid another lib to load.)

[Knah-Tsaeb]

I recently use http://phpqrcode.sourceforge.net/ it's work fine.

[sebsauvage]

It looks good. Thanks.

[edent]

I've helped develop a simple PHP based QR generator.

https://github.com/edent/QR-Generator-PHP

Doesn't need anything other than to be dropped into a directory. Happy to help integrate it, if you'd like?

[tolima]

http://invx.com don't work anymore as it's use in shaarli. (or may be it's just on my shaarli)

[nodiscc]

Fixed by @sebsauvage in af77b2f

This can be closed.