Adding functionality to support Signed Assemblies

This is to support signed assemblies by using a Build Configuration called SignedRelease (You may have to add a configuration named that, but do not need to change anything else related to it).

I am not sure if anyone else would find it useful, but I would absolutely love a "SharpRepository" library in Nuget along side a "SharpRepository - Signed" 

Managing the nuget packages has to be a nightmare, but I would love to see support for this.