add libffi v3.1 (needed for glib > 2.29)
add initial makefile for libffi
update glib v2.16.6 - merge in glib v2.41.2

note: the "build/win32/vs8" dir was removed before 2.41.2, but it's being left in for now. later, it should be removed.
update makefile for glib 2.41.2
update libogg v1.3.0 - merge in libogg v1.3.2
update makefile for libogg 1.3.2
update libvorbis v1.3.3 - merge in libvorbis v1.3.4
update makefile for libvorbis 1.3.4
re-apply libvorbis patch from poti bug 17892, git rev 9029731
re-apply patch allowing building tests to be optional in libvorbis, rev 7eb7e2d
update flac v1.2.1 - merge in flac v1.3.0
update makefile for flac 1.3.0
add DEPVERSIONS, listing current versions of the deps in the repo/branch