- #5822
- update `Microsoft.AspNet.WebApi.Client` package version
- remove remaining few `$(PackageTargetFallback)` settings
- remove .NET Standard-specific files
- they duplicate what Microsoft.AspNet.WebApi.Client now provides
- necessary only if cross-compiling a PCL version of the WebApiCompatShim
- add type forwarding for the removed `public` types
- reenable .NET Framework WebApiCompatShim tests
- add breaking change record for `MediaTypeFormatterMatchRanking` value change
- version of this type in the shim lacked the `MatchOnRequestWithMediaTypeMapping` value