Prevent two enforce tasks to run concurently. This could happen when manually issueing an enforce.

Conflicts:
	enforcer-ng/src/daemon/engine.c
	enforcer-ng/src/enforcer/enforce_cmd.cpp
	enforcer-ng/src/enforcer/enforce_task.cpp

Conflicts:
	enforcer-ng/src/daemon/engine.c
	enforcer-ng/src/enforcer/enforce_cmd.cpp
	enforcer-ng/src/enforcer/enforce_task.cpp
Never call a key dead. In 1.x a dead key was never displayed. Call it retired.
If DS is seen but not all TTLs passed (ds would be rumoured) call it active instead of ready.
Check the pidfile to prevent 2 instances running at once.

Conflicts:
	enforcer-ng/src/daemon/engine.c

Conflicts:
	enforcer-ng/src/daemon/engine.c
lost a "}" in the cherry pick
Made some changes to ods_enforcer_count_starts()/stops() and ods_start_enforcer_timeshift(). This seems to fix some intermediate problems.
ods_enforcer_start_timeshift() did not take a timeout in develop
Do not pass negative value to kill. It will try to signal itself/processgroup
Merge pull request #53 from jelu/fix-keygen-test-dev

Port changes made in #50 / #51 to develop
Merge pull request #52 from yschaeff/bb

Backport a couple of fixes from client_stderr branch
OPENDNSSEC-184: Add --zone filter to 'ods-enforcer rollover list' command. Also remove the verbose option as this was not used. And fix a bug where the command wasn't processed properly and always reported too many arguments.
Merge pull request #55 from saradickinson/OPENDNSSEC-184_sara

OPENDNSSEC-184: Add --zone filter to 'ods-enforcer rollover list' command
Restore the ordering of the help output to what is was before the restructure.
Merge pull request #56 from yschaeff/help_ordering

Restore the ordering of the help output to what is was before the restru...
print error if start fails
display pid on start and stop
Merge pull request #57 from yschaeff/start_errmsg

OPENDNSSEC-557
OPENDNSSEC-554: On 'zone add/delete' only do incremental changes to internal zones.xml file to speed things up
OPENDNSSEC-604: Fix the ds-X and key export commands. Also do some nit changes to usage and logging.
Merge pull request #59 from saradickinson/OPENDNSSEC-554_2

OPENDNSSEC-554: On 'zone add/delete' only do incremental changes to inte...
Merge pull request #60 from saradickinson/enforcer-ng_usage_updates

OPENDNSSEC-604: Fix the ds-X and key export commands. Also do some nit c...