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.
Respond to a SIGUSR1 or SIGUSR2 signal by configuring itself
for autosave, saving a new file, or overwriting the current,
respectively, and sending itself a SIGTERM (which _generally_
causes Tux Paint to quit, depending on where you are in the UI).
Closes https://sourceforge.net/p/tuxpaint/feature-requests/188/
