Beta quality drop of Objective C Support.

- Add more to the ObjC dir readme.
- Merge the ExtensionField and ExtensionDescriptor to reduce overhead.
- Fix an initialization race.
- Clean up the Xcode schemes.
- Remove the class/enum filter.
- Remove some forced inline that were bloating things without proof of performance wins.
- Rename some internal types to avoid conflicts with the well know types protos.
- Drop the use of ApplyFunctions to the compiler/optimizer can do what it wants.
- Better document some possible future improvements.
- Add missing support for parsing repeated primitive fields in packed or unpacked forms.
- Improve -hash.
- Add *Count for repeated and map<> fields to avoid auto create when checking for them being set.
diff --git a/objectivec/Tests/GPBTestUtilities.h b/objectivec/Tests/GPBTestUtilities.h
index 6ae68c3..44c8084 100644
--- a/objectivec/Tests/GPBTestUtilities.h
+++ b/objectivec/Tests/GPBTestUtilities.h
@@ -35,6 +35,8 @@
 @class TestMap;
 @class TestPackedTypes;
 @class TestPackedExtensions;
+@class TestUnpackedTypes;
+@class TestUnpackedExtensions;
 @class GPBExtensionRegistry;
 
 
@@ -55,8 +57,12 @@
            repeatedCount:(uint32_t)count;
 - (void)setPackedFields:(TestPackedTypes *)message
           repeatedCount:(uint32_t)count;
+- (void)setUnpackedFields:(TestUnpackedTypes *)message
+            repeatedCount:(uint32_t)count;
 - (void)setPackedExtensions:(TestPackedExtensions *)message
               repeatedCount:(uint32_t)count;
+- (void)setUnpackedExtensions:(TestUnpackedExtensions *)message
+              repeatedCount:(uint32_t)count;
 - (void)setAllMapFields:(TestMap *)message numEntries:(uint32_t)count;
 
 - (TestAllTypes *)allSetRepeatedCount:(uint32_t)count;