remove isLastLine from interface - use stack instead; fix null reference if resolve of TypeDefinition fails

ICSharpCode.NRefactory/CSharp/OutputVisitor/IOutputFormatter.cs

@@ -39,6 +39,6 @@ namespace ICSharpCode.NRefactory.CSharp
 		
 		void NewLine();
 		
-		void WriteComment(CommentType commentType, string content, bool isLastLine = false);
+		void WriteComment(CommentType commentType, string content);
 	}
 }

ICSharpCode.NRefactory/CSharp/OutputVisitor/OutputVisitor.cs

@@ -2147,9 +2147,7 @@ namespace ICSharpCode.NRefactory.CSharp
 				// "1.0 / /*comment*/a", then we need to insert a space in front of the comment.
 				formatter.Space();
 			}
-			bool isContinuing = (comment.NextSibling is Comment && ((Comment)comment.NextSibling).CommentType == comment.CommentType);
-			
-			formatter.WriteComment(comment.CommentType, comment.Content, !isContinuing);
+			formatter.WriteComment(comment.CommentType, comment.Content);
 			lastWritten = LastWritten.Whitespace;
 			return null;
 		}

ICSharpCode.NRefactory/CSharp/OutputVisitor/TextWriterOutputFormatter.cs

@@ -88,7 +88,7 @@ namespace ICSharpCode.NRefactory.CSharp
 			indentation--;
 		}
 		
-		public void WriteComment(CommentType commentType, string content, bool isLastLine = false)
+		public void WriteComment(CommentType commentType, string content)
 		{
 			WriteIndentation();
 			switch (commentType) {