Finish porting to Windows

[vmarkovtsev]

@juanjux I added appveyor config which generates two build artifacts - mingw and msvc++ archived prefixes.

You need to manually enable AppVeyor for bblfsh/libuast here: https://ci.appveyor.com/projects/new

[juanjux]

Excellent work dealing with the Beast. I just added the project to appveyor.

[vmarkovtsev]

"Project not found or access denied." at https://ci.appveyor.com/project/bblfsh/libuast I guess we need to enable public readonly access (not sure)

[juanjux]

Done. I've given view and run build permissions for users. I'm waiting for travis to finish to merge this, but it seems it doesn't work very well today.

[juanjux]

Mmmm, still now showing, let me check it.

[juanjux]

Found the problem, since I logged with my github user it's at:

https://ci.appveyor.com/project/juanjux/libuast

Do we have a bblfsh user for appveyor or do I register a new one?

[vmarkovtsev]

AppVeyor offers you to enable projects in all the organizations you are allowed to. For example, I can enable it for our projects in src-d but not in bblfsh. I guess we need to ask Máximo to grant you the permissions.

[juanjux]

Yes, I see src-d projects but not bblfsh, @mcuadros could you fix the permissions?

[mcuadros]

Done, you need to push something

[vmarkovtsev]

I will push the badge