[2.2] Fixed the characters encode problems.

Comment update:
JSON do not return UTF-8 encode so this cause several encoding problem in cinnamon, especially in Desklets and Applets settings. This code try to a allow UTF-8 encode instead of Ascii encode to solve the problem.

More info about the problem: 
https://github.com/linuxmint/Cinnamon/issues/2245

Please see this another posibility:
https://developer.gnome.org/glib/stable/glib-Character-Set-Conversion.html

Thanks...