To make it known (when the warning message is emitted) what
version this was deprecated in and when it may be removed
in add those parameters to the 'removed_kwarg' decorator so that
users of conductors are aware of this information.

Change-Id: Iacc97831ccd96d68cea4bd7e65a967b5ff9e7dc5

If the zk node disappears underneath the conductor before it attempts to
abandon or consume a job, consumption/abandonment would fail with an
uncaught exception, killing the conductor. Catching excp.NotFound corrects
this.

Change-Id: Iaa7d0d8d0ebbc76973f16d717cc3137c75fbfec2

Removed _dead.wait from the stop method and added a wait method to
explicitly wait for graceful shutdown.  Implicitly waiting for
graceful shutdown in the stop method is leading to potential
deadlock situations when conductor is running in the main thread
and a signal handler is used to kick off stop/shutdown.

Also in larger systems, it is desirable to be able to initiate
shutdown on all running services then wait/join everything together
so as not to force a serial shutdown pattern.

Change-Id: Ic74dab22b09100c5b653d12c2518f83a1bf8e859

Add a new logging BLATHER level to easily allow its
usage for messages that are below the normal DEBUG level
such as compilation information and scope lookup info
which can be very verbose in logs if always enabled.

Change-Id: I828211403bd02bfd6777b10cdcfe58fb0637a52c

Instead of blocking up the whole test suite when a latch or
event was not decremented to its desired value (or not set for
an event) we should use a reasonably high value that we use
when waiting for those actions to occur and verify that when those
wait() functions return that we have reached the desired state and
if not either raise an exception or stop further testing.

Fixes bug 1363739

Change-Id: I8b40282ac2db9cabd48b0b65c8a2a49610d77c4f

To avoid having one set of options coming from `engine_conf`
and another set of options coming from `kwargs` and another set
coming from `engine_conf` if it is a URI just start to shift
toward `engine_conf` being deprecated and `engine` being a string
type only (or a URI with additional query parameters) and having
any additional **kwargs that are provided just get merged into the
final engine options.

This adds a new helper function that handles all these various
options and adds in a keyword argument `engine` that will be shifted
to in a future version (in that future version we can also then
remove the `engine_conf` and just stick to a smaller set of option
mechanisms).

It also adjusts all examples to use this new and more easier to
understand format and adjusts tests, conductor interface to use
this new more easily understandable style of getting an engine.

Change-Id: Ic7617057338e0c63775cf38a24643cff6e454950

To make it easier to add in a multi-threaded conductor
convert the base dispatch_job function to return a future
object. This future object will contain a single result,
whether the job should be consumed or abandoned. In the
single threaded conductor its dispatch_job function will
return a future, after completing the job (in a multi
threaded conductor it would not return a future after
doing the work).

Change-Id: I077334820d36c64e272e93d158e3a0cd0d66a937