- update to 0.13:
* Link to libsystemd instead of shipping a copy of sd-daemon
* Move D-Bus policy to datadir
* Install the D-Bus interface description
* Other fixes accumulated over the years from various distributions
* Add meson build files (autotools stays available for now)
* Replace the use of as with xxd for including a file as a string, which avoids
* some pitfalls (#15 and portability problems). The tarball contains the
* resulting file, so xxd is not necessary when building using autotools
* Move rtkit-daemon.service from graphical.target to multi-user.target (#12)
* Make libsystemd an optional dependency (#13)