[winswitch] issue with forwarding x to a lower res monitor from a virtual Xvfb

[Antoine Martin]

>>> $ lsb_release -a
>>> LSB
>>> Version:	core-2.0-amd64:core-2.0-noarch:core-3.0-amd64:core-3.0-noarch:core-3.1-amd64:core-3.1-noarch:core-3.2-amd64:core-3.2-noarch:core-4.0-amd64:core-4.0-noarch:core-4.1-amd64:core-4.1-noarch:security-4.0-amd64:security-4.0-noarch:security-4.1-amd64:security-4.1-noarch
>>> Distributor ID:	Ubuntu
>>> Description:	Ubuntu 14.04.3 LTS
>>> Release:	14.04
>>> Codename:	trusty
>>> xpra  is at v0.15.8-2 and xvfb is at v1.15.1-0ubuntu2.7
>> Xdummy is problematic on Ubuntu - it is disabled for most Ubuntu versions.
> I have got xserver-xorg-video-dummy 1:0.3.7-1build1 installed. Yet do
> you mean it will be problematic?!
Just a warning about Ubuntu' s changes to Xorg.
If Xdummy does work reliably on Ubuntu Trusty (TBC), then we should 
change the default config that we ship for this particular release.

Cheers
Antoine