* Workaround problems when opening solution files in Visual Studio (#4569)
Changes:
* Condense Routing.sln into HttpAbstractions.sln
* Workaround NU1105 by adding all ProjectReferences to the .sln
* Workaround exceptions in the ReferencesHostBridge by moving Reference items to a temporary item group
* Add a 'startvs.cmd' script for launching VS with the right env variables
* Remove RangeHelper test project
* Move RangeHelper tests into StaticFiles.Tests and add target for NPM restore
* Convert Session to use Reference and move to Middleware folder (#4576)
* Add RoutingSample.Web to HttpAbstractions.sln
Changes:
* Condense Routing.sln into HttpAbstractions.sln
* Workaround NU1105 by adding all ProjectReferences to the .sln
* Workaround exceptions in the ReferencesHostBridge by moving Reference items to a temporary item group
* Add a 'startvs.cmd' script for launching VS with the right env variables
* Remove RangeHelper test project
* Move RangeHelper tests into StaticFiles.Tests and add target for NPM restore
* Replace the aspnet/JsonPatch git submodule and merge the master branch of its source to this repo
* Likewise for aspnet/DotNetTools
* And aspnet/HtmlAbstractions
* merge latest infrastructure changes from the release/2.2 branch
As a part of simplifying the way we build ASP.NET Core, the BrowserLink and Scaffolding repos and the packages they produce will be independent from aspnet/AspNetCore.