Remove NUnit3 project (deprecated) (akkadotnet#152)

Akka.TestKit.Nunit.sln

@@ -7,10 +7,6 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Akka.TestKit.NUnit", "src\A
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Akka.TestKit.NUnit.Tests", "src\Akka.TestKit.NUnit.Tests\Akka.TestKit.NUnit.Tests.csproj", "{D63223FA-03F5-4B32-A6EC-668F718C0826}"
 EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Akka.TestKit.NUnit3", "src\Akka.TestKit.NUnit3\Akka.TestKit.NUnit3.csproj", "{62A7BBA3-2AA6-4F9B-8ACA-15C3863C026E}"
-EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Akka.TestKit.NUnit3.Tests", "src\Akka.TestKit.NUnit3.Tests\Akka.TestKit.NUnit3.Tests.csproj", "{FF91B397-1E60-4B94-99A1-B534C7BB91A5}"
-EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{873747EF-ACF9-4BB2-90C1-052BFA3C84F2}"
 	ProjectSection(SolutionItems) = preProject
 		README.md = README.md
@@ -31,14 +27,6 @@ Global
 		{D63223FA-03F5-4B32-A6EC-668F718C0826}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{D63223FA-03F5-4B32-A6EC-668F718C0826}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{D63223FA-03F5-4B32-A6EC-668F718C0826}.Release|Any CPU.Build.0 = Release|Any CPU
-		{62A7BBA3-2AA6-4F9B-8ACA-15C3863C026E}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{62A7BBA3-2AA6-4F9B-8ACA-15C3863C026E}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{62A7BBA3-2AA6-4F9B-8ACA-15C3863C026E}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{62A7BBA3-2AA6-4F9B-8ACA-15C3863C026E}.Release|Any CPU.Build.0 = Release|Any CPU
-		{FF91B397-1E60-4B94-99A1-B534C7BB91A5}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{FF91B397-1E60-4B94-99A1-B534C7BB91A5}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{FF91B397-1E60-4B94-99A1-B534C7BB91A5}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{FF91B397-1E60-4B94-99A1-B534C7BB91A5}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE