rake build: pipe xcodebuild to xcpretty
rake build: pipe xcodebuild to xcpretty

1. Speeds up the build
2. Easier on the eyes
3. Enables xcodebuild in travis which strictly limits
   log output; xcodebuild often exceeds this limit.

specta/expecta,jmburges/expecta,iosdev-republicofapps/expecta,jmoody/expecta,PatrykKaczmarek/expecta,iosdev-republicofapps/expecta,iguchunhui/expecta,tonyarnold/expecta,ashfurrow/expecta,tonyarnold/expecta,iguchunhui/expecta,Bogon/expecta,jmoody/expecta,wessmith/expecta,modocache/expecta,Lightricks/expecta,PatrykKaczmarek/expecta,Lightricks/expecta,jmoody/expecta,jmburges/expecta,jmburges/expecta,udemy/expecta,jmoody/expecta,iosdev-republicofapps/expecta,ashfurrow/expecta,tonyarnold/expecta,modocache/expecta,modocache/expecta,suxinde2009/expecta,suxinde2009/expecta,modocache/expecta,udemy/expecta,tonyarnold/expecta,Bogon/expecta,ashfurrow/expecta,wessmith/expecta,PatrykKaczmarek/expecta,ashfurrow/expecta,jmburges/expecta,PatrykKaczmarek/expecta,iosdev-republicofapps/expecta