xcodeproj 0.19.0

on Ruby Gems

• PlistHelper: Now the plutil tool is used to save the files if available
  to produce output consistent with Xcode.
  Fabio Pelosin
• Project: Added support for adding file references to sub-projects.
  Fabio Pelosin
• Config: The config class now properly handles quotes in OTHER_LDFLAGS.
  Fabio Pelosin
• PBXGroup: Now file references to Xcode projects are properly handled and
  setup. Also the ObjectDictionary class has been improved and now can be
  used to edit the attributes using it.
  Fabio Pelosin
  Xcodeproj#172
• Constants: Support XCTest as product type and don't fail for
  PBXNativeTarget#symbol_type on unknown product types.
  Marius Rackwitz
  Xcodeproj#176
• Workspace: Now a template is used to produce the same formatting of Xcode.
  Fabio Pelosin
• Project: Improved validation of object attributes.
  Fabio Pelosin
• Project: Completed support for dictionaries.
  Fabio Pelosin
• Project: Added possibility to disable xcproj via an environment variable.
  Fabio Pelosin

Bug Fixes

• Project: Fixed reference counting issue when deleting sub-projects.