core: added a few plugin state testing functions.
lua-bindings: added function to test if a plugin is loaded (and running).
lua-bindings: try not to lose file inclusion Lua error messages

Propagate file inclusion Lua error messages back to the caller.
If we're handling a try-include (errors are ignored), log any
Lua runtime  errors as a warning (since the user probably wanted
include-if-exists semantics).
lua-utils: be a bit more robust if fed with invalid objects.
mdb: added functions for handling database trigger event data.
lua-utils: try harder getting complex object getter/setter cases right.

Try to handle better cases when a (potentially extensible) object
class has both predefined members and an overridden setter/getter
with or without native/whitelisted members. The current semantics
is roughly the following:

  1) check and handle if the field corresponds to a predefined member
  2) if there is a setfield/getfield declared and the field is marked
     native or no fields have been marked native at all, pass it to
     setfield/getfield
  3) if there is no setfield/getfield or there is one but it did not
     handle the field (returned 0), pass it to setext/getext if the
     class is extensible

Note that in principle we should treat it an error if a field declared
as native is not handled by setfield/getfield. Currently we don't.

Also note that with these semantics it probably would be better to
forget about marking members as native and just remove native
whitelisting altogether. We'd then instead always pass every non-
predeclared field to setfield/getfield, then try setext/getext if
this setfield/getfield did not handle the field (IOW returned 0).

This would also get us rid of the potential ambiguity of what to do
if a field has been declared native but then setfield/getfield does
not handle it.
lua-utils: patch the stack for {s,g}etfield during init + fix a bad pattern of thinkos.

This could/should still be improved a bit. Now setfield and getfield
must use top-relative addressing and also be extremely careful not
to screw up the stack by popping it too much. Probably it would be
much betters to patch the stack and then invoke setfield or getfield
via lua_pcall which would both protect and clean up the stack for us.
This'll probably need another iteration...

This patch also fixes a pattern of horribly embarrassing thinkos in
the setter/getter and initializer status checking / fallback selection
logic.
lua-utils: oops... don't patch the stack quite so eagerly.

During the last merge/rebase cycle I screwed up and a small
object infra patch fell of. Undo that damage now.
lua-utils: add missing boolean support for funcbridge Lua call.
sample-config: test how the basis for a modular config could look like.
common: rewind the DBus message after each signal handler.
domain-control: add missing CDECL-wrapper to client header.
domain-control: fix an error message typo.
sample-config: don't load superfluous D-Bus plugin.
resource-dbus: shared and mandatory property sigs 's' -> 'b'.
lua-5.2: core: allow building against Lua >= 5.2.
lua-5.2: resource: allow building against Lua >= 5.2.
lua-5.2: build-sys: allow building against a specified Lua version.
lua-5.2: added Lua specfile patches for 'peaceful coexistence'.

Added two patches that allow Lua-5.2.x and Lua-5.1.x to co-
exist without conflicts with whichever version you happen to
have installed on your system. To get the additional version
installed, take the Fedora source RPM of the version you want,
patch its specfile with the patch in this commit, then build
and install. So rougly:

    rpm -ivh <uri-of-fedora-lua.src.rpm>
    patch -p0 < <patch-from-this-commit>
    rpm -bb ~/rpmbuild/SPECS/lua.spec
    rpm -ivh ~/rpmbuild/RPMS/<arch>/lua-*.rpm
daemon: honour overridden sysconfdir.