Documentation is now maintained in a separate source repository,
'tuxpaint-docs', which allows for easier and more consisten
translation of the documentation. Pulling in initial version of
these docs, which contain a variety of minor updates (and also a
few which had previously only been available as plain TXT are now
available as HTML).
Pulling in the English stuff.
Using XDG's user dir settings to determine where pictures are
stored for a user (e.g., "~/Pictures" -- used as a fallback).
May be overridden using "--exportdir".
Also, while I was updating some docs, replace references to
"Mac OS X" with "macOS", the new name of that OS these days.
They're in a new location over on John P.'s website
(should we purhapse integrate them into Tux Paint proper?)
(h/t sechidis & whoever on #tux4kids IRC channel who helped them)
Documenting Mark Kim's recent changes:
* Less CPU-hungry progress bar (during Stamp loading)
* Verbose debugging options
* (Also, mentioned debugging _at all_, in INSTALL.txt)
Bumping version to 0.9.23a, to match the test build he's working
on for macOS.
