This introduces a new event type

   VIR_DOMAIN_EVENT_ID_IO_ERROR_REASON

This event is the same as the previous VIR_DOMAIN_ID_IO_ERROR
event, but also includes a string describing the cause of
the event.

Thus there is a new callback definition for this event type

typedef void (*virConnectDomainEventIOErrorReasonCallback)(virConnectPtr conn,
                                                           virDomainPtr dom,
                                                           const char *srcPath,
                                                           const char *devAlias,
                                                           int action,
                                                           const char *reason,
                                                           void *opaque);

This is currently wired up to the QEMU block IO error events

* daemon/remote.c: Dispatch IO error events to client
* examples/domain-events/events-c/event-test.c: Watch for
  IO error events
* include/libvirt/libvirt.h.in: Define new IO error event ID
  and callback signature
* src/conf/domain_event.c, src/conf/domain_event.h,
  src/libvirt_private.syms: Extend API to handle IO error events
* src/qemu/qemu_driver.c: Connect to the QEMU monitor event
  for block IO errors and emit a libvirt IO error event
* src/remote/remote_driver.c: Receive and dispatch IO error
  events to application
* src/remote/remote_protocol.x: Wire protocol definition for
  IO error events
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor.h,
  src/qemu/qemu_monitor_json.c: Watch for BLOCK_IO_ERROR event
  from QEMU monitor

In a couple of cases typos meant we were firing the wrong type
of event. In the python code my previous commit accidentally
missed some chunks of the code.

* python/libvirt-override-virConnect.py: Add missing python glue
  accidentally left out of previous commit
* src/conf/domain_event.c, src/qemu/qemu_monitor_json.c: Fix typos
  in event name / method name to invoke

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

* README: New file describing what each file is used for
* livvirt-override.c, libvirt-override.py, libvirt-override-api.xml,
  libvirt-override-virConnect.py: Manually written code overriding
  the generator
* typewrappers.c, typewrappers.h: Data type wrappers
* generator.py: Automatically pre-prend contents of libvirt-override.py
  to generated libvirt.py. Output into libvirt.py directly instead of
  libvirtclass.py. Don't generate libvirtclass.txt at all. Write C
  files into libvirt.c/.h directly
* Makefile.am: Remove rule for creating libvirt.py from libvirt-override.py
  and libvirtclass.py, since generator.py does it directly

  by Ben Guthro
daniel