windows releases do not include halide.cmake (and related files)

[cbartnl]

Windows builds do not include halide.cmake (and related files). Including these files would make working with halide on windows much easier (particularly now VS2017 has native cmake support). But it seems to depend on some missing config files, which are not generated for windows?

[alexreinking]

This is getting fixed in #4644 . halide.cmake is deprecated in favor of imported targets / find_package.