Add ObjC helpers for Any WKT.

- Capture the ObjC prefix used when generating the the file.
- Track the containing type on descriptors.
- Mark descriptors where the message class name got a suffix added to it.
- Expose a fullName property on Descriptors.
- Add helpers for packing/unpacking Any messages.
- Bump the ObjC runtime version number. Since we added methods and invoke them
  in the generated code, ensure the code is running against a matching version.
  Otherwise, someone could compile against headers, but run with a framework
  that is older and get unknown selector failures.  This should trip clearer
  messaging.

Fixes https://github.com/google/protobuf/issues/1674
diff --git a/objectivec/DevTools/compile_testing_protos.sh b/objectivec/DevTools/compile_testing_protos.sh
index 35a8504..6cc32da 100755
--- a/objectivec/DevTools/compile_testing_protos.sh
+++ b/objectivec/DevTools/compile_testing_protos.sh
@@ -93,6 +93,7 @@
 # sources can be generated from them.
 
 CORE_PROTO_FILES=(
+  src/google/protobuf/any_test.proto
   src/google/protobuf/unittest_arena.proto
   src/google/protobuf/unittest_custom_options.proto
   src/google/protobuf/unittest_enormous_descriptor.proto