Windows support

[egoroof]

Do you plan to add Windows support?

[springmeyer]

Windows support is not planned.

If someone wants to attempt this, these are the steps that would need to happen:

• rely on the cross platform https://github.com/mapbox/mason-js instead of the non-portable to windows bash scripts
• port the codebase to use the header-only https://github.com/mapbox/protozero/ library instead of libprotobuf (since that would be hard to precompile and maintain for windows)
• precompile libfreetype for windows - could potentially use https://github.com/mapbox/windows-builds/blob/master/scripts/build_freetype.bat
• enable https://ci.appveyor.com support and ensure all tests pass on windows