* TracerBuilder depedency injection improvements.
* Fixes and API updates.
* Update skipped test.
* Tweak.
* Tweaks.
* Test fix.
* Turn on options in TracerProviderBuilderBase.
* Updated CHANGELOGs.
* Added XML comments to AddOpenTelemetryTracing methods.
* Tweaks.
* Added export helpers and restored removed API from hosting library so that there is no breakage during upgrades.
* Export extension tweaks.
* Tweak.
* Tracer builder improvements.
* Fix hosting multiple configurations test.
* Cleanup.
* Cleanup and fixes.
* Added "UseOpenTelemetry" extensions.
* Cleanup.
* Code review.
* Code review.
* Rename SDK extension "Configure" and restore "Add" in the hosting lib.
* Doc clarification.
* Some test coverage.
* README updates.
* Fix double dispose of TracerProvider when using Sdk.CreateTracerProviderBuilder.
* AddExporter tests.
* More test coverage.
* More test coverage.
* Code review.
Mikel Blanchard