Added monochrome effect and placeholders in the PrinterDestination, so Jens can fill in the blanks... :)

git-svn-id: http://svn.code.sf.net/p/greenshot/code/trunk@2467 7dccd23d-a4a3-4e1f-8c07-b4c1b4018ab4

GreenshotPlugin/Core/Effects.cs

@@ -101,6 +101,16 @@ namespace Greenshot.Core {
 		}
 	}
 
+	/// <summary>
+	/// MonochromeEffect
+	/// </summary>
+	public class MonochromeEffect : IEffect {
+		public Image Apply(Image sourceImage, out Point offsetChange) {
+			offsetChange = Point.Empty;
+			return ImageHelper.CreateMonochrome(sourceImage);
+		}
+	}
+
 	/// <summary>
 	/// InvertEffect
 	/// </summary>