Planning to run 'tidy' on the HTML doc files. Documenting the
arguments I'm providing to 'tidy', for future reference,
within the RELEASE.txt file.
Also, cleaned up and improved RELEASE.txt.
TOYAMA Shin-ichi noticed that when building for Win32 under mingw/msys,
an #include of "librsvg-cairo.h" was also necessary.
He also bumped the version # in win32/resources.rc
(and I put his credit in there).
I updated docs/RELEASE.txt to mention that .rc file also needing
updated when preparing a new release.
I forgot to make sure macos/Info.plist had the latest version # and
release date, before tagging and releasing source code. Adding a checklist
of places to double-check for properly-updated version #s and/or release dates.