Change dependencies to work with python or python3

libxml2, pycairo-python3, and pygobject3
Dependencies are now soft (<after>) so python or python3 is required to be on the module list unless you're using a meta-module that includes it (e.g., one of the gtk-osx-python meta-modules).
Remove spurious dependencies
Add autogen template for freetype


Autogen.sh doesn't run configure automagically as jhbuild expects.
Unstable: Build with either Python 2.7 or Python3
Fix sha256 and build type for pycairo-python3
Unstable: Build git masters of libxml2 and libxslt
Correct download file type of python-3.3.0.tar.xz
Use configure for vala-bootstrap, not autogen.sh

vala-bootstrap's `autogen.sh` doesn't automatically run `configure`,
so the build breaks for lack of a `Makefile`. In addition,
vala-bootstrap already includes `configure`, so `autogen.sh` isn't
necessary.
Merge pull request #12 from ptomato/patch-3

Use configure for vala-bootstrap, not autogen.sh
Replace the vala tarball in modulesets-unstable with vala-bootstrap

Which ensures that modulesets-unstable is always built with the latest
stable vala -- and that vala-git will build, not necessarily the case
if the released tarball gets out of date.
Modulesets: Make gtk+-3.0 dependent upon gdk-pixbuf-gtk3

Thanks to Phil Chimento for point out the oversight.
Change libproxy branch to tag

Libproxy is a SVN repository, so when checking out a tag we have to
specify tag instead of revision.
Preserve previous $CFLAGS for liboil

If the existing CFLAGS are clobbered and replaced with
-DHAVE_SYMBOL_UNDERSCORE, then a 64-bit compiler will be used on
a 64-bit system even if a 32-bit compiler has been specified. This
causes the build to fail when it tries to compile 32-bit assembly
language.
Remove gstreamer-common

gstreamer-common is meant to be checked out as a submodule of the
various gstreamer repos, not as a separate module - it doesn't build
by itself.

Also, fixed a typo.
Merge pull request #15 from ptomato/patch-4

Remove gstreamer-common
Merge pull request #14 from ptomato/patch-liboil

Preserve previous $CFLAGS for liboil
Merge pull request #13 from ptomato/patch-3

Change libproxy branch to tag
Fix typo in stable.harbuzz, add deps in other harfbuzzes
Update gtk+-3.0; fixes disappearing scrollbar slider.
Make libgnome-keyring dependencies consistent across modules