Added Object Mapping block helpers to RKObjectManager and RKObjectMapping. These enable you to perform ad-hoc object mapping very easily. Extended RKObjectRouter to match on superclasses if no specific route is found. This is helpful when using mocked objects with frameworks like Kiwi. fixes #238

Code/ObjectMapping/RKObjectMapping.h

@@ -123,6 +123,53 @@ relationship. Relationships are processed using an object mapping as well.
  */
 + (id)mappingForClass:(Class)objectClass;
 
+/**
+ Returns an object mapping useful for configuring a serialization mapping. The object
+ class is configured as NSMutableDictionary
+ */
++ (id)serializationMapping;
+
+#if NS_BLOCKS_AVAILABLE
+/**
+ Returns an object mapping targeting the specified class. The RKObjectMapping instance will
+ be yieled to the block so that you can perform on the fly configuration without having to
+ obtain a reference variable for the mapping.
+ 
+ For example, consider we have a one-off request that will load a few attributes for our object. 
+ Using blocks, this is very succinct:
+ 
+    [[RKObjectManager sharedManager] postObject:self delegate:self block:^(RKObjectLoader* loader) {
+        loader.objectMapping = [RKObjectMapping mappingForClass:[Person class] block:^(RKObjectMapping* mapping) {
+            [mapping mapAttributes:@"email", @"first_name", nil];
+        }];
+    }];
+ */
++ (id)mappingForClass:(Class)objectClass block:(void(^)(RKObjectMapping*))block;
+
+/**
+ Returns serialization mapping for encoding a local object to a dictionary for transport. The RKObjectMapping instance will
+ be yieled to the block so that you can perform on the fly configuration without having to
+ obtain a reference variable for the mapping.
+ 
+ For example, consider we have a one-off request within which we want to post a subset of our object
+ data. Using blocks, this is very succinct:
+ 
+    - (BOOL)changePassword:(NSString*)newPassword error:(NSError**)error {
+        if ([self validatePassword:newPassword error:error]) {
+            self.password = newPassword;
+            [[RKObjectManager sharedManager] putObject:self delegate:self block:^(RKObjectLoader* loader) {
+                loader.serializationMapping = [RKObjectMapping serializationMappingWithBlock:^(RKObjectMapping* mapping) {
+                    [mapping mapAttributes:@"password", nil];
+                }];
+            }];
+        }
+    }
+ 
+ Using the block forms we are able to quickly configure and send this request on the fly.
+ */
++ (id)serializationMappingWithBlock:(void(^)(RKObjectMapping*))block;
+#endif
+
 /**
  Add a configured attribute mapping to this object mapping