Many documentation subdirs contained only a translated version
of the GNU GPL (COPYING.txt), and no translated version of any
Tux Paint documentation.
Moved them all into a COPYING/ subdir, so that now the only
translated documentation subdirs that exist are those that
containa at least _some_ translated Tux Paint documentation.
There are a ton of wishful-thinking traslation subdirs under docs/
which contain nothing but files which say "Please see..." and
directs to the English version.
Removing them, because they're just cluttering thigns,
and it makes it hard to tell whether any translations actually _do_
exist (which may require attention; e.g. revising for a new
release).
