Cake.Build doesn't generate description for nuget and non-sdk projecs

[nils-a]

Cake.Build doesn't generate description for nuget and non-sdk projecs

[nils-a]

The fact here, is that NuGetPack (like nuget.exe) has two very distinct usages: One operating on a project file and one operating on a .nuspec file and not all settings that are available in the NuGetPackSettings are used for both usages.

• We should make this more clear in the docs.
• Some properties could probably be set in some other way. (Like the Description property could most likely be set by adding it to the msbuild properties.)
• Properties that are set, but are not used in one of the use cases could produce a warning so that it is more obvious that this property is set but not being used.