coverage.sh: Refresh build system (and meta information).
sysdb(1): Be more verbose about the exit status when using the -c option.
documentation: Unified author information.
sysdbql(7): Document the query language.
sysdb(1): Added sysdbql(7) to "see also".
sysdbql(7): Fixed a typo.
sysdb(7): Added a manpage providing an overview of SysDB.
sysdbd(1): Documented all signals handled by the daemon.
Makefile: Added missing headers to _HEADERS variables.
Added initial version of the release notes.
Make libsysdb and libsysdbclient private libraries for now.

The API is not yet stable enough for that purpose.
Makefile: Add ReleaseNotes to a dist tarball.