Refactoring c# projects (#544)

Small Refactoring c# projects, e.g.
* add days
* remove StartupObject
* Fix Approval tests for NUnit
* Use Environment.NewLine in Xunit tests
* Added + fixed README.md
* Removed global.json

csharp.NUnit/README.md

@@ -1,23 +1,24 @@
-# Gilded Rose starting position in Csharp Core
+# Gilded Rose starting position in C# NUnit
 
 ## Build the project
 
-Use your normal build tools. 
+Use your normal build tools to build the projects in Debug mode.
+For example, you can use the `dotnet` command line tool:
 
-## Run the TextTest fixture from the Command-Line
+``` cmd
+dotnet build GildedRose.sln -c Debug
+```
+
+## Run the Gilded Rose Command-Line program
 
 For e.g. 10 days:
 
-```
-GildedRoseTests/bin/Debug/net8.0/GildedRoseTests 10
+``` cmd
+GildedRose/bin/Debug/net8.0/GildedRose 10
 ```
 
-You should make sure the command shown above works when you execute it in a terminal before trying to use TextTest (see below). If your tooling has placed the executable somewhere else, you will need to adjust the path above.
-
-
-## Run the TextTest approval test that comes with this project
-
-There are instructions in the [TextTest Readme](../texttests/README.md) for setting up TextTest. You will need to specify the GildedRoseTests executable and interpreter in [config.gr](../texttests/config.gr). Uncomment this line:
-
-    executable:${TEXTTEST_HOME}/csharpcore/GildedRoseTests/bin/Debug/net8.0/GildedRoseTests
+## Run all the unit tests
 
+``` cmd
+dotnet test
+```