Windows build

[jeromegn]

Either through appveyor or travis' new Windows early access.

It is also necessary to build and use V8 pre-built lib files from https://github.com/superfly/libv8 (which currently does not build for Windows)

[mrkurt]

Or Azure Pipelines. :D

[jeromegn]

Deno now uses pre-built V8 libs and therefore we have easier access to Windows V8.

[jeromegn]

Deno stopped using pre-built libv8, we're on our own!