Change base class of ToolBarCommand from ToolStripMenuItem to ToolStripButton.

This fixes the bug forum-8878 (focus rectangle is drawn for disabled toolbar buttons).

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/branches/3.0@3751 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/Main/ICSharpCode.Core.WinForms/ToolBar/ToolBarCommand.cs

@@ -10,7 +10,7 @@ using System.Windows.Forms;
 
 namespace ICSharpCode.Core.WinForms
 {
-	public class ToolBarCommand : ToolStripMenuItem, IStatusUpdate
+	public class ToolBarCommand : ToolStripButton, IStatusUpdate
 	{
 		object caller;
 		Codon codon;