virsh: support remaining domain events

virsh: support remaining domain events

Earlier, I added 'virsh event' for lifecycle events, to get the
concept approved; this patch finishes the support for all other
events, although the user still has to register for one event
type at a time.  A future patch may add an --all parameter to
make it possible to register for all events through a single
call.

* tools/virsh-domain.c (vshDomainEventWatchdogToString)
(vshDomainEventIOErrorToString, vshGraphicsPhaseToString)
(vshGraphicsAddressToString, vshDomainBlockJobStatusToString)
(vshDomainEventDiskChangeToString)
(vshDomainEventTrayChangeToString, vshEventGenericPrint)
(vshEventRTCChangePrint, vshEventWatchdogPrint)
(vshEventIOErrorPrint, vshEventGraphicsPrint)
(vshEventIOErrorReasonPrint, vshEventBlockJobPrint)
(vshEventDiskChangePrint, vshEventTrayChangePrint)
(vshEventPMChangePrint, vshEventBalloonChangePrint)
(vshEventDeviceRemovedPrint): New helper routines.
(cmdEvent): Support full array of event callbacks.

Signed-off-by: Eric Blake <eblake@redhat.com>