obt returns libxml2 structures directly, so anyone linking against it better also link to libxml2
make the obt .pc file do -lobt, not -lobrender
Set up work for making a 3.5 prerelease. Set version stuff to 3.5.0-rc1. Copy the CHANGELOG from 3.4-working. Rename the obt-4.0 and obrender-4.0 pkgconfig stuff to obt-3.5 and obrender-3.5 Rename the "render" directory to "obrender" so that the public headers can be installed in <obrender/*>