OS X: don't autodetect spelling language.

Language detection must be explicitly disabled for explicitly set
language (when known, such as in Poedit) to have any effect.
chversion.sh: don't update nonexistent make-distrib.sh.
chversion.sh: don't put version into PO files.

Now that they are Crowdin-managed, the ID is just "poedit" anyway.
Move MoveApplication.strings to macosx/.

Manage these translations internally in Poedit rather than relying on
upstream to merge our translations.
Remove unused support files for OS X disk images.

OS X versions are now distributed as ZIP archives, not disk images.
Remove leftover DMG support files form the repository.
Fix possible endless recursion in text editing events handling.