Add guidelines regarding dependency to Cake

While technically not required, adding a dependency in the addin nuspec file to the Cake package in the version agains which the addin was compiled could help users to see in which Cake versions the addin works.

The downside of this approach is that the Cake package will be downloaded to the addin folder in this case.

Whats considered best practice here?

The issue concerns dependency declarations in an addin nuspec file and the Cake package version used to compile the addin. First determine the preferred dependency practice, including whether downloading Cake into the addin folder is acceptable; the work is done when the decision is documented as clear guidance for addin authors.

Written by the indexing model from the issue text.