0.15.0

Breaking

• [Project] Now the provided path is always expanded on initialization.
  Gordon Fontenot
  #121

Enhancements

• [Constants] Bumped last know SDK versions.
  Fabio Pelosin
  #141
• [Constants] Removed empty OTHER_LDFLAGS setting to match Xcode's behaviour.
  Gordon Fontenot
• [Constants] Bumped last known Xcode version to 5.1.
  Romans Karpelcevs
  #138

Bug Fixes

• [Extension] Fixed intermittent Xcodeproj::PlistHelper.write_plist error.
  Eloy Durán