g_utf8_strescape implementation in glib

[Igor Gnatenko <i gnatenko brain gmail com>]

Hi developers!
In this bug in glib (https://bugzilla.gnome.org/show_bug.cgi?id=89548)
Owen Taylor asked for "Include a UTF-8 safe escaping function". In 2002
year.
In 2010 developer Christian Dywan created attachment with patch.
Now 2013 year and glib has undergone many changes.
I created new patch
(https://bugzilla.gnome.org/show_bug.cgi?id=89548#c10) (based on
Christian patch) and I want you to write review.
I think that this patch is very important as bug in empathy depends of
this bug.

-- 
Best Regards,
Igor Gnatenko