Temporary workaround for duplicated objects caused by RKInMemoryMappi…

…ngCache. refs #612

There are some issues with the current implementation of the RKInMemoryMappingCache that
are allowing the creation of duplicated objects. This commit switches the default cacheStrategy
to RKFetchRequestMappingCache. The primary key branch (#613) contains architecture
improvements that allow for a robust fix to the issues in the memory based cache.

Code/CoreData/RKManagedObjectStore.m

@@ -27,6 +27,7 @@
 #import "RKAlert.h"
 #import "RKDirectory.h"
 #import "RKInMemoryMappingCache.h"
+#import "RKFetchRequestMappingCache.h"
 #import "NSBundle+RKAdditions.h"
 #import "NSManagedObjectContext+RKAdditions.h"
 
@@ -117,7 +118,7 @@ - (id)initWithStoreFilename:(NSString *)storeFilename inDirectory:(NSString *)ni
         self.primaryManagedObjectContext = [self newManagedObjectContext];
 
 
-        _cacheStrategy = [[RKInMemoryMappingCache alloc] init];
+        _cacheStrategy = [[RKFetchRequestMappingCache alloc] init];
 
         // Ensure there is a search word observer
         [RKSearchWordObserver sharedObserver];