Check whether the receiver specifies forwardingTarget for the given s…

…elector.

After exhausting all other possible outcomes, add a call to -forwardingTargetForSelector: to check whether there is another object that should receive the message.  If so, then send try sending the message to that target. This allows classes defined in Nu to take advantage of "fast" message forwarding by implementing -forwardingTargetForSelector:

objc/NuObject.m

@@ -244,6 +244,10 @@ - (id) sendMessage:(id)cdr withContext:(NSMutableDictionary *)context
         // Messaging null is ok.
         else if (self == Nu__null) {
         }
+        else if ( (target = [target forwardingTargetForSelector:sel]) ) {
+            //NSLog(@"found forwarding target: %@ for selector: %@", target, NSStringFromSelector(sel));
+            result = [target sendMessage:cdr withContext:context];
+        }
         // Otherwise, call the overridable handler for unknown messages.
         else {
             //NSLog(@"calling handle unknown message for %@", [cdr stringValue]);
@@ -258,7 +262,6 @@ - (id) sendMessage:(id)cdr withContext:(NSMutableDictionary *)context
     [result autorelease];
     return result;
 }
-
 - (id) evalWithArguments:(id)cdr context:(NSMutableDictionary *)context
 {
     return [self sendMessage:cdr withContext:context];