Update CHANGES.markdown to indicate UIKit+PivotalSpecHelperStubs now requires ARC
Update CHANGES.markdown to indicate UIKit+PivotalSpecHelperStubs now requires ARC

mjstallard/PivotalCoreKit,briancroom/PivotalCoreKit,pivotaltracker/PivotalCoreKit,gudatcomputers/PivotalCoreKit,jfuchs/PivotalCoreKit,jfuchs/PivotalCoreKit,pivotal/PivotalCoreKit,joemasilotti/PivotalCoreKit,idoru/PivotalCoreKit,joemasilotti/PivotalCoreKit,idoru/PivotalCoreKit,gudatcomputers/PivotalCoreKit