Mark some methods in AbstractProject as virtual for compatibility with 4.1 AddIns.

src/Main/Base/Project/Src/Project/AbstractProject.cs

@@ -351,13 +351,13 @@ namespace ICSharpCode.SharpDevelop.Project
 		}
 		
 		[Browsable(false)]
-		public bool IsStartable {
+		public virtual bool IsStartable {
 			get {
 				return GetOrCreateBehavior().IsStartable;
 			}
 		}
 		
-		public void Start(bool withDebugging)
+		public virtual void Start(bool withDebugging)
 		{
 			GetOrCreateBehavior().Start(withDebugging);
 		}
@@ -368,7 +368,7 @@ namespace ICSharpCode.SharpDevelop.Project
 		/// <exception cref="ProjectStartException">Occurs when the project cannot be started.</exception>
 		/// <returns>ProcessStartInfo used to start the project.
 		/// Note: this can be a ProcessStartInfo with a URL as filename!</returns>
-		public ProcessStartInfo CreateStartInfo()
+		public virtual ProcessStartInfo CreateStartInfo()
 		{
 			return GetOrCreateBehavior().CreateStartInfo();
 		}
@@ -428,7 +428,7 @@ namespace ICSharpCode.SharpDevelop.Project
 		/// <summary>
 		/// Creates a new projectItem for the passed itemType
 		/// </summary>
-		public ProjectItem CreateProjectItem(IProjectItemBackendStore item)
+		public virtual ProjectItem CreateProjectItem(IProjectItemBackendStore item)
 		{
 			return GetOrCreateBehavior().CreateProjectItem(item);
 		}
@@ -460,7 +460,7 @@ namespace ICSharpCode.SharpDevelop.Project
 		/// Returns ItemType.None for unknown items.
 		/// Every override should call base.GetDefaultItemType for unknown file extensions.
 		/// </summary>
-		public ItemType GetDefaultItemType(string fileName)
+		public virtual ItemType GetDefaultItemType(string fileName)
 		{
 			return GetOrCreateBehavior().GetDefaultItemType(fileName);
 		}
@@ -558,7 +558,7 @@ namespace ICSharpCode.SharpDevelop.Project
 			return projectOptions;
 		}
 		
-		public void ProjectCreationComplete()
+		public virtual void ProjectCreationComplete()
 		{
 			GetOrCreateBehavior().ProjectCreationComplete();
 		}