Fall back to full loading on .NET Core (dotnet#3394)

Update changelog for 1.5.1 (dotnet#3350)

* Update changelog for 1.5.1

* Address feedback

Replace CacheSizeInMb setting with DataMaxAgeInCache and DataMinTimeI…

…nCache in stream providers (dotnet#3126)

Update version to 1.5.0-beta1