implements unified people, see heardrwt#33.

unify duplicates records if the contact exists in multiple sources, see
http://stackoverflow.com/a/11480352/255463 and heardrwt#33.

RHAddressBook/RHAddressBook.h

@@ -105,6 +105,9 @@ typedef NS_ENUM(NSUInteger, RHAuthorizationStatus) {
 @property (nonatomic, readonly, copy) NSArray *peopleOrderedByFirstName;
 @property (nonatomic, readonly, copy) NSArray *peopleOrderedByLastName;
 
+- (NSArray *)peopleUnifiedUsingDefaultSource;
+- (NSArray *)peopleUnifiedUsingSource:(RHSource *)source;
+
 -(NSArray*)peopleWithName:(NSString*)name;
 -(NSArray*)peopleWithEmail:(NSString*)email;
 -(RHPerson*)personForABRecordRef:(ABRecordRef)personRef; //returns nil if ref not found in the current ab, eg unsaved record from another ab. if the passed recordRef does not belong to the current addressbook, the returned person objects underlying personRef will differ from the passed in value. This is required in-order to maintain thread safety for the underlying AddressBook instance.

RHAddressBook/RHAddressBook.m

@@ -645,6 +645,45 @@ -(NSArray*)peopleOrderedByLastName{
     return [self peopleOrderedBySortOrdering:kABPersonSortByLastName];
 }
 
+/**
+ *
+ *
+ *  @return NSArray
+ */
+- (NSArray *)peopleUnifiedUsingDefaultSource
+{
+    __block NSArray *result = nil;
+
+    rh_dispatch_sync_for_addressbook(self, ^{
+        result = arc_retain([self peopleUnifiedUsingSource:[self defaultSource]]);
+    });
+
+    return arc_autorelease(result);
+}
+
+/**
+ *
+ *
+ *  @param source
+ *
+ *  @return NSArray
+ */
+- (NSArray *)peopleUnifiedUsingSource:(RHSource *)source
+{
+    __block NSArray *result = nil;
+
+    rh_dispatch_sync_for_addressbook(self, ^{
+        CFArrayRef peopleRefs = ABAddressBookCopyArrayOfAllPeopleInSource(_addressBookRef, source.recordRef);
+
+        if (peopleRefs) {
+            result = arc_retain([self peopleUnifiedForABRecordRefs:peopleRefs]);
+            CFRelease(peopleRefs);
+        }
+    });
+
+    return arc_autorelease(result);
+}
+
 -(NSArray*)peopleWithName:(NSString*)name{
     __block NSArray *result = nil;
     rh_dispatch_sync_for_addressbook(self, ^{
@@ -778,6 +817,39 @@ -(NSArray*)peopleForABRecordRefs:(CFArrayRef)peopleRefs{
     return [NSArray arrayWithArray:people];
 }
 
+/**
+ *
+ *
+ *  @param peopleRefs
+ *  @see http://stackoverflow.com/a/11480352/255463
+ *
+ *  @return NSArray
+ */
+- (NSArray *)peopleUnifiedForABRecordRefs:(CFArrayRef)peopleRefs
+{
+    if (!peopleRefs) return nil;
+
+    NSMutableSet *people = [NSMutableSet set];
+
+    rh_dispatch_sync_for_addressbook(self, ^{
+        for (CFIndex i = 0; i < CFArrayGetCount(peopleRefs); i++) {
+            NSMutableSet *contactSet = [NSMutableSet set];
+            ABRecordRef personRef = CFArrayGetValueAtIndex(peopleRefs, i);
+            [contactSet addObject:(__bridge id) personRef];
+
+            NSArray *linkedRecordsArray = (__bridge NSArray *) ABPersonCopyArrayOfAllLinkedPeople(personRef);
+            [contactSet addObjectsFromArray:linkedRecordsArray];
+
+            RHPerson *person = [self personForABRecordRef:personRef];
+            if (person) [people addObject:person];
+
+            CFRelease(personRef);
+        }
+    });
+
+    return people.allObjects;
+}
+
 -(RHPerson*)personForABRecordID:(ABRecordID)personID{
 
     __block ABRecordRef recordRef = NULL;