Created Unassigned: Use custom ApiDescriptionComparer with ApiExplorer [1478]

Code in https://aspnetwebstack.codeplex.com/SourceControl/latest#src/System.Web.Http/Description/ApiExplorer.cs removes all duplicates based on HTTP method + path

This is not sometimes the desired logic.

Can we implement a injectable ApiDescriptionComparer so the consumer of the ApiExplorer can control what duplicates are removed and what are needed.