Set up Nuget package release

[filipw]

Ideally we'd split into master and dev branches and we can release pre release packages automatically from dev, and once we are ready / happy enough with the functionalities, we can merge to master which will release the stable package.

[panesofglass]

Related to #39

[panesofglass]

You could also keep master as latest code (released as alpha? beta?) and use tags to release final versions. See example at https://github.com/Tachyus/gluon/blob/master/build.fsx#L75-L82 or https://github.com/freya-fs/freya/blob/master/build.fsx#L166-L176.

[filipw]

yep that would work too