[ovs-dev] appveyor - windows autobuild service

[Ben Pfaff]

The travis autobuilder has been pretty awesome for GNU/Linux continuous
integration.  I'd like to have autobuilders for other platforms too.
After a few minutes searching, I see that appveyor.com offers a similar
service, with similar Github integration, for Windows builds.  If anyone
has time and inclination to integrate this with OVS, I'd appreciate it.