To be able to test the QEMU monitor code, we need to have a fake
QEMU monitor server. This introduces a simple (dumb) framework
that can do this. The test case registers a series of items to
be sent back as replies to commands that will be executed. A
thread runs the event loop looking for incoming replies and
sending back this pre-registered data. This allows testing all
QEMU monitor code that deals with parsing responses and errors
from QEMU, without needing QEMU around
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>