Allow CommonReactiveSource to be created free threaded
Merge pull request #627 from reactiveui/allow_common_reactive_source_to_be_created_in_background

Allow CommonReactiveSource to be created free threaded
Rename some projects to be more consistent.
App.config nobody loves you.
App.config nobody loves you.
Get Rx from NuGet.
Get Splat from NuGet.
Update configs.
Add Rx-Xaml.
Delete the targets file.
Add Rx-WinRT.
No more Platforms and Mobile.
Get Json.Net from NuGet.
Add Rx-Testing and Json.Net
Remove all references to nuget.targets.
Manually add Rx for now.
Remove unused assemblies.
Get xUnit and NRefactory from NuGet.
Revert "No more Platforms and Mobile."

This reverts commit 3987b165d239e2409041306ebacddd69b1de5bf3.
Rename portable folder.