The example C event loop code is a nasty hack and not compliant
with the require API semantics. Delete this, so that developers
don't mistakenly copy it. Instead call the new public event loop
APIs.

Update the python event loop example, so that it can optionally
use the public event APIs, as an alternative to the pure python
code. The pure python event code is a good working example, so
don't delete it.

Also make the python example use a read only connection to avoid
authentication prompts

* examples/domain-events/events-c/event-test.c: Replace event
  loop code with use of public APIs
* examples/domain-events/events-python/event-test.py: Allow
  optional use of new public event APIs

If the event loop takes a very long time todo something, it is
possible for the 'self pipe' buffer to become full at which
point the entire event loop + remote driver deadlock. Use a
boolean flag to ensure we have strict one-in, one-out behaviour
on writes/reads of the 'self pipe'

Make it easy to change debugging if being used by a client program.

The events demo program is slightly misleading printing

  myDomainEventCallback1 EVENT: Domain f14i686(-1) Added

which is not distinguishing Add vs Update events. It should have
been doing

  myDomainEventCallback1 EVENT: Domain f14i686(-1) Defined Updated

* examples/domain-events/events-python/event-test.py: Fully print
  event detail info string

The generator was disabled for the new event callbacks, since they
need to be hand written. This patch  adds the C and python glue to
expose the new APIs in the python binding. The python example
program is extended to demonstrate of the code

* python/libvirt-override.c: Registration and dispatch of events
   at the C layer
* python/libvirt-override-virConnect.py: Python glue for events
* examples/domain-events/events-python/event-test.py: Demo use
  of new event callbacks

The conversion from seconds to milliseconds should only be done for
actual delays >= 0, not for the magic -1 value used for infinite
timeouts.
Signed-off-by: NPhilipp Hahn <hahn@univention.de>

The existing python demo for domain events does not fully
implement the event loop contract. This makes the code useless
for real world applications. This change re-writes the demo so
that it has a full event loop implementation which is suitable
for application usage & better demonstrates integration

* examples/domain-events/events-python/event-test.py: Rewrite
  to include a real world usable event loop implementation

by running this command:
git ls-files -z | xargs -0 perl -pi -0777 -e 's/\n\n+$/\n/'
This is in preparation for a more strict make syntax-check
rule that will detect trailing blank lines.

  python/libvir.py python/libvirt_wrap.h python/types.c:
  adds support for events from the python bindings, also
  improves the generator allowing to embbed per function
  definition files, patch by Ben Guthro
* examples/domain-events/events-python/event-test.py: also
  adds a programming example
Daniel