[File sorting] Upper case are displayed before lower case files.

[DrUm78]

Files with upper case as the 1st letter are listed before lower case files, whatever the letter is. This bug does not occur on GMenu2X on RG350 FYI.

Steps to reproduce:

1. Name a file "Z.zip" (upper case) for instance and one "a.zip".
2. Browse the folder where those files are with GMenu2X
3. Notice that "Z.zip" is displayed before "a.zip"

Screenshot:

[DrUm78]

Fixed in DrUm78@345f75a.