make ppa-publish: Also build package for Ubuntu 14.10
Makefile: Fix comment to match 99aefc4
Makefile: Ubuntu ppa-publish shouldn't depend on Fedora specfile

This dates back to when the "ppa-publish" rule was first added in
639d8dc6. I think it must have been a mistake.
debian packaging: "make clean" removes all leftover debian files

After "make deb" failed because I had an incorrect gpg key
configuration, running "make deb" again would fail with:

    tar: extra/stb-tester_0.20-202-g1f2dd21-dirty-1/.debian.tar:
    Cannot open: No such file or directory

The only way to fix this was by removing `extra/debian/1/`. I don't know
why it wasn't already in `.gitignore`.

I'd rather not have to remember the `git clean -Xfd` incantation, so
that's what `make clean` does now (before it was missing a whole lot of
build artifacts, and I'd rather not maintain that list manually). Note
that `make clean` can be called from outside a git repo (in particular,
the debian packaging scripts call `make clean` from an unpacked
tarball), hence the `|| true`.
Makefile: Cleanup: Move variables closer to use site

In particular it's helpful to see what "debian_base_release" is.

This is consistent with the placement of other packaging variables like
DPKG_OPTS, DPUT_HOST, and rpm_topdir.
Makefile: Cleanup long lines

I'm trying to track down a bug with the debian packaging (not all
dependencies seem to be specified, because the .dsc file isn't being
created before it's referenced by the dpkg-source recipe), so seeing all
the code at once helps me to make sense of all this.
Makefile: Cleanup: Replace patsubst with Substitution References

See https://www.gnu.org/software/make/manual/html_node/Substitution-Refs.html

I find this much clearer, because it leads with the variable instead of
having as the last parameter to patsubst.
Makefile: Document value of % and $* in debian packaging rules
Makefile: More visible section headers (comments)
debian packaging: Move source package creation out of Makefile

...into separate script. Each time we run "make deb" we remove the
existing source package and build it from scratch (thanks to the
"debian-src-pkg/%/: FORCE" rule we had) so we don't actually gain
anything by using make's dependency tracking. Instead we lose a lot of
readibility because the order of operations isn't in linear order like
an imperative script is, and because the use of "%" and "$*" obscures
what the actual values are (compare
"stb-tester_$(VERSION)-%.debian.tar.xz" with
"stb-tester_$version-$release.debian.tar.xz").

I, at least, think this is clearer. I've also added a rule ("make
debsrc") to build all Ubuntu source packages before publishing them.

I also reordered the rules in the makefile so that the targets a user
would use (deb, debsrc, ppa-publish) come before the implementation
details.

I transfer the debian control files to the build directory with `cp`
instead of tarring & untarring them. I think Will was using tar to alter
the files' timestamps to get deterministic builds, but he didn't get
100% there so let's not bother with this.
debian packaging: Use the full dput target name

As per instructions on
https://launchpad.net/~stb-tester/+archive/ubuntu/stb-tester
debian packaging: Ubuntu 13.10 (Saucy) reached End Of Life

It's no longer supported by Canonical (since July 17, 2014), and
Launchpad will no longer build Saucy packages in the PPAs.
Merge branch 'deb-packaging-cleanup'

* deb-packaging-cleanup:
  debian packaging: Ubuntu 13.10 (Saucy) reached End Of Life
  debian packaging: Use the full dput target name
  debian packaging: Move source package creation out of Makefile
  Makefile: More visible section headers (comments)
  Makefile: Document value of % and $* in debian packaging rules
  Makefile: Cleanup: Replace patsubst with Substitution References
  Makefile: Cleanup long lines
  Makefile: Cleanup: Move variables closer to use site
  debian packaging: "make clean" removes all leftover debian files
  Makefile: Ubuntu ppa-publish shouldn't depend on Fedora specfile
  Makefile: Fix comment to match 99aefc4
  make ppa-publish: Also build package for Ubuntu 14.10
release notes: 0.21 release date and summary