Use NUnit's RequiresSTA to fix failing unit tests.

src/AddIns/BackendBindings/Scripting/Test/Console/InsertConsoleCompletionDataTestFixture.cs

@@ -10,6 +10,7 @@ using NUnit.Framework;
 namespace ICSharpCode.Scripting.Tests.Console
 {
 	[TestFixture]
+	[RequiresSTA]
 	public class InsertConsoleCompletionDataTestFixture
 	{
 		ScriptingConsoleCompletionData completionData;

src/AddIns/BackendBindings/Scripting/Test/Console/ScriptingConsoleTextEditorTests.cs

@@ -15,6 +15,7 @@ using NUnit.Framework;
 namespace ICSharpCode.Scripting.Tests.Console
 {
 	[TestFixture]
+	[RequiresSTA]
 	public class ScriptingConsoleTextEditorTests
 	{
 		ScriptingConsoleTextEditor consoleTextEditor;

src/AddIns/BackendBindings/Scripting/Test/Console/ThreadSafeScriptingConsoleTextEditorTests.cs

@@ -15,6 +15,7 @@ using NUnit.Framework;
 namespace ICSharpCode.Scripting.Tests.Console
 {
 	[TestFixture]
+	[RequiresSTA]
 	public class ThreadSafeScriptingConsoleTextEditorTests
 	{
 		ThreadSafeScriptingConsoleTextEditor threadSafeConsoleTextEditor;

src/AddIns/BackendBindings/Scripting/Test/ICSharpCode.Scripting.Tests.csproj

@@ -174,8 +174,5 @@
       <Name>ICSharpCode.Scripting</Name>
     </ProjectReference>
   </ItemGroup>
-  <ItemGroup>
-    <None Include="app.config" />
-  </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.Targets" />
 </Project>

src/AddIns/BackendBindings/Scripting/Test/app.config

@@ -1,14 +0,0 @@
-<configuration>
-	<configSections>
-		<sectionGroup name="NUnit">
-			<section name="TestRunner"
-			         type="System.Configuration.NameValueSectionHandler" />
-		</sectionGroup>
-	</configSections>
-	<NUnit>
-		<TestRunner>
-			<!-- Valid values are STA,MTA. Others ignored. -->
-			<add key="ApartmentState" value="STA" />
-		</TestRunner>
-	</NUnit>
-</configuration>