Add a "j2k decode" region console command that allows a manual request for a JPEG2000 decode of an asset

For debugging purposes.

OpenSim/Region/Framework/Interfaces/IJ2KDecoder.cs

@@ -35,6 +35,13 @@ namespace OpenSim.Region.Framework.Interfaces
     public interface IJ2KDecoder
     {
         void BeginDecode(UUID assetID, byte[] j2kData, DecodedCallback callback);
-        void Decode(UUID assetID, byte[] j2kData);
+
+        /// <summary>
+        /// Provides a synchronous decode so that caller can be assured that this executes before the next line
+        /// </summary>
+        /// <param name="assetID"></param>
+        /// <param name="j2kData"></param>
+        /// <returns>true if decode was successful.  false otherwise.</returns>
+        bool Decode(UUID assetID, byte[] j2kData);
     }
 }