Fix #381

Prefer to use vnc websocket port if exists. You should edit xml like this (the websocket attribute):

<graphics type='vnc' port='5900' websocket='5700' listen='127.0.0.1'>
   <listen type='address' address='127.0.0.1'/>
</graphics>
Merge branch 'websocket' of git://github.com/tolbkni/webvirtmgr into tolbkni-websocket
Update version