added windows Mono solution setup for library build

[Ondra09]

No description provided.

[Dav1dde]

What is this and why would it be useful if it is included?
(Also please squash the commits into one)

[Ondra09]

Hi Dave,
it's only mono develop environment settings fro building your library under windows. I understand that you may not want to have your project flooded with build settings for all possible development environments.

Best, Ondrej

[Dav1dde]

Thanks for the clarification, thinking of it.

[MartinNowak]

One of the key features of dub is the ability to generate Mono-D projects.
So it should be sufficient to go with #14.

[Dav1dde]

Right, thanks for the reminder, I wanted to setup the DUB package.