Removing executable bit from icon.
Replacing icons again.
Changes the select2 highlight color to magenta.

This probably belongs into the theme, but i'm not touching those until
there is a decision on how we proceed with icon fonts. This branch
should only live as long as that question remains unanswered.
provides magenta version of excel.png

Magenta versions for the other file types are probably needed but I haven't spotted those beeing used in the application yet