test-path: move all related test files to a specific directory To avoid polluting test/

test-engine: fix access to unit load path Also add a bit of debugging output to help diagnose problems, add missing units, and simplify cppflags. Move test-engine to normal tests from manual tests, it should now work without destroying the system.

units: remove RefuseManualStart from units which are always around In a normal running system, non-passive targets and units used during early bootup are always started. So refusing "manual start" for them doesn't make any difference, because a "start" command doesn't cause any action. In early boot however, the administrator might want to start on of those targets or services by hand. We shouldn't interfere with that. Note: in case of systemd-tmpfiles-setup.service, really running the unit after system is up would break the system. So e.g. restarting should not be allowed. The unit has "RefuseManualStop=yes", which prevents restart too.

units: introduce new Documentation= field and make use of it everywhere This should help making the boot process a bit easier to explore and understand for the administrator. The simple idea is that "systemctl status" now shows a link to documentation alongside the other status and decriptionary information of a service. This patch adds the necessary fields to all our shipped units if we have proper documentation for them.

relicense to LGPLv2.1 (with exceptions) We finally got the OK from all contributors with non-trivial commits to relicense systemd from GPL2+ to LGPL2.1+. Some udev bits continue to be GPL2+ for now, but we are looking into relicensing them too, to allow free copy/paste of all code within systemd. The bits that used to be MIT continue to be MIT. The big benefit of the relicensing is that closed source code may now link against libsystemd-login.so and friends.

units: make fedora/single.service standard and rename it to rescue.service