Add image/x-tiff-multipage mime-type

It's a fake mime-type that can be used by applications using a simple
image loader (such as gdk-pixbuf) to find other applications capable of
opening multi-page TIFF images.

See https://bugzilla.gnome.org/show_bug.cgi?id=335959
Updated translations
Rename "Microsoft icon" to "Windows icon"

The cursors are from "Windows" and MacOS X icons also use the OS name,
not the vendor's name. This also makes the name match with gdk-pixbuf's
naming.
Add magic for ODB files

Fixes ODB file association being missing in dolphin

See https://bugzilla.redhat.com/1158778
https://bugs.freedesktop.org/show_bug.cgi?id=85645