Add changes by Xcode to xccheckout.
Update CocoaFlow/Transport submodule.
Add fake message receiver for testing purposes.
Update transport as a message receiver.
Fix spec example descriptions.
Add examples for setting properties.
Remove fake runtime
Update spec to use fake message receiver.
Add changes by Xcode to xccheckout.
Make property examples pending due to Quick issue.
Update implementation to cause spec to pass.
Fix spec example descriptions.