pdns: Kill all spawned processes

Pipe backend spawned processes can still be alive after the pdns_server-instance was killed.
If the children remain alive, sockets will not be released, and the pdns_server-instance can't be respawned.

To be sure that all the spawned processes are killed, we must kill by using the process GID.
To be able to do the soft reloads, pdns_server-instance is declared as process group lider.

Also, all forced kills must kill by GID, not by PID, so all the processes would properly die.

Signed-off-by: Igor Maravic <igor@spotify.com>
Signed-off-by: Alexey Lapitsky <alexey@spotify.com>
Clean up after DynListener crash

When DynListener crashes, kill all processes from his parent PGRP.

This way we'll certanly close the pdns.controlsocket (no more hanging pdns_control processes)
and we'll kill the processes that aren't managable via pdns_control any more.
Add timeout to pdns_control connect, send and recv calls

If any of the connect, send and recv calls are timedout, TimeoutException is thrown.
main loop catches that exception and returns code 2.
code 1 is returned for all other exceptions.

In init.d script we now have 3 states:
UP
DOWN
UNRESPONSIVE

If the pdns_server is unresponsive, it will be killed.
After that, script continues as usual.
Clean up after the pdns_server-instance

Make sure that all children are killed after the pdns_server-instance dies
PDNS should always be the leader of the process group

That way, we can properly kill all of it's subprocesses!
Fix docs for export-etc-hosts-search-suffix

Fixes #1097
remove ancient INSTALL file from gmysqlbackend
remove old TODO file from bindbackend
code cleanup gmysqlbackend
remove updateDNSSECOrderAndAuthAbsolute from bind backend
disarm debug output
remove stamp-h.in file
use QClassEnum for qclass values
pdnssec check-zone, fix DNSKEY checks
Merge pull request #1098 from zeha/fix-1097

Fix docs for export-etc-hosts-search-suffix
Merge pull request #1104 from mind04/pdnssec

pdnssec check-zone, fix DNSKEY checks
move mysql/pgsql/sqlite3 .sql files to backend directories
remove PowerDHCP? files
remove long gone tools from pdns/Makefile.am
Merge pull request #1105 from mind04/movesql

move mysql/pgsql/sqlite3 .sql files to backend directories