Now that IdentityServer v3 is almost done, it makes sense to “deprecate” some of the older projects. Especially all of the functionality of AuthorizationServer is completely replaced by the IdSrv3 feature set.
AuthorizationServer is actually a pretty small and compact code base, and a relatively complete implementation of OAuth2 including a simple authorization model based on clients, applications and scopes. Also there are no major bugs (that we know about) or feature gaps.
IOW – if you want to use AS, simply make it part of your own code base and feel free to change it at will. Check the wiki for documentation.
If somebody wants to take over the project, contact me.