bus: don't include the introspected object in list of subobjects
bus: make bus message dump output a bit smaller
bus: don't fail if GetAll() is used to get properties of the built-in interfaces
bus: it is OK to have signals with multiple parameters
autogen: use -O0 for "autogen.sh c" after all

-Og actually breaks gdb still, so let's stick to -O0 for now, but
introduce "autogen.sh g" for those who don't need gdb.
bus: make sure we can match well-known names
update TODO
machined: port over to libsystemd-bus
git: indicate that tabs are never OK in the systemd tree
bus: fix build
build-sys: remove default CFLAGS assignment