Update event loop example programs to demonstrate best practice

Update event loop example programs to demonstrate best practice

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