Bump TravisCI image to Xcode 7.2
Bump TravisCI image to Xcode 7.2

yiplee/MagicalRecord,pronebird/MagicalRecord,spex-app/MagicalRecord,pronebird/MagicalRecord,yiplee/MagicalRecord,simoncoulton/MagicalRecord,spex-app/MagicalRecord,spex-app/MagicalRecord,simoncoulton/MagicalRecord