Rename `RKSearchTokenizer` to `RKStringTokenizer` to better reflect its utility
Fix build issues and warnings for RKSearchExample project due to Core Data build changes
Update `rake validate` to build using xctool instead of xcodebuild for more readable output
Put `RKStringTokenizer` into the public headers
Update AFNetworking submodule reference to 1.3.2
Bump CocoaPods dependency to 0.23.0
Add Rake task for verifying that RestKit continues to build without direct dependencies on Core Data