No support for deps=msvc

[RedBeard0531]

I did a quick search through the code and it looks like it doesn't support deps = msvc and msvc_deps_prefix. We use this even on POSIX platforms as a simple way to allow scripts to indicate which files they depend on without requiring them to generate well-formed make files: https://github.com/RedBeard0531/mongo_module_ninja/blob/5324999/build.py#L165-L174

[michaelforney]

Why is generating well-formed makefiles a problem? Isn't it just a matter of writing target: source instead of Note: including file: source? Or is your concern with whitespace and special characters?

I'm open to adding this, but it is low priority for me, so I'm not sure when I'll get to it.