Remove avoidsNetworkAccess property in favor of leveraging NSURLCache capabilities under the hood.

Code/Network/RKHTTPRequestOperation.h

@@ -53,4 +53,10 @@
  */
 @property (nonatomic, strong) NSSet *acceptableContentTypes;
 
+/**
+ Whether the response received a 304 response, whether via the initial request, or by virtue of
+ cache revalidation occurring from NSURLCache.
+ */
+@property (nonatomic, readonly) BOOL wasNotModified;
+
 @end