UI hangs while establishing QMP monitor connection

[JayFoxRox]

The UI hangs after hitting the start button, until QMP is connected.

This means that UI elements like the log that is being added in #48 are not refereshed, which means a large number of log messages are suddenly shown, once the connection is established.
The "Start" button won't change into "Stop" for about a second on my machine - this makes the UI feel unresponsive.

To avoid this, the connection loop should be improved / replaced:

xqemu-manager/main.py

Lines 288 to 302 in 00f3bf0

	self._p = subprocess.Popen(cmd)
	i = 0
	while True:
	print('Trying to connect %d' % i)
	if i > 0: time.sleep(1)
	try:
	self._qmp = QEMUMonitorProtocol(('localhost', 4444))
	self._qmp.connect()
	except Exception as e:
	if i > 4:
	raise
	else:
	i += 1
	continue
	break