add Documentation= reference to knot-resolver.service

This makes "systemctl help knot-resolver" bring up the appropriate man
page.

See merge request !39

This makes "systemctl help knot-resolver" bring up the appropriate man
page.

Control socket activation

This branch provides reasonable configs for full systemd socket activation for kresd.

See merge request !36

This is a fully-socket-activated knot-resolver service that can run as
a non-priivleged user named knot-resolver.

When run under systemd supervision, accept a control socket from the
supervisor if the name supplied is "control".

See FileDescriptorName= in systemd.socket(5) for more details.

this module is superseded by http module, removing

iterator already checks this and also chain length,
however these checks were omitted in the rrcache
CNAME unroll loop

there are cases where switches or middle-boxes
block DNS/UDP answers >512 octets completely,
this gives user an option to mitigate that.
however, there are authoritatives serving
large answers that don't support TCP, so it's
a compromise as always

in normal mode, only final CNAME target is refetched, but
not intermediate CNAMEs. intermediate CNAMEs are *never* cached,
but they are used to get final name for requery. in strict mode now,
every CNAME target is explicitly fetched even if it's a chained CNAME.

more kresd.8 cleanup



See merge request !35

emacs turds should never make it into git



See merge request !34

Doc cleanup

This is a simple cleanup of documentation

See merge request !33

Suggested by @ondrej.

when whole interface is passed and some of the addresses are not bindable,
the daemon will print them, but will continue to bind to the rest of the
addresses

fixes #80

all relevant modules now support running in
forked mode and polling workers for information.
for example graphite module can poll stats from
all workers and then aggregate before sending,
or HTTP module can run on the process group leader
only and then poll workers for information.

forks are connected with IPC pipes to process
group leader and can execute expressions on its
behalf. so running commands over all workers
is easy now:

> hostname() -- single
localhost

> map 'hostname()' -- all
localhost
localhost
localhost

* the dygraphs are now leveraged for drawing as
  canvas based drawing is much faster than
  svg based rickshaw
* refreshed theme and layouts, code cleanup

the e638f9fb introduced deduplication
for queries over UDP, the idea is to track same queries and answer
only once, however that introduces both constant processing and
memory overhead and could break clients who count packet loss
by queries sent/received. disabling for now.