[Patch] req.remote_user is not always set

[Andras Korn]

Hi,

I played around with this plugin a bit because it didn't seem to do anything.

Apparently, req.remote_user isn't (always?) set, so I modified it to use req.authname instead. It now works for me, but I don't know if this is a correct solution.

The attached patch contains this change as well as:

• messages and HTML template (of 0.12 branch) translated into English (sorry, not proper l10n, I just updated the hardcoded strings);
• it retrieves displayName instead of cn to get the name (this should really be configurable, I suppose);
• it now supports non-ascii characters in names;
• some code typos were fixed;
• I added some debug logging.

[figaro]

See also #3171.