0.28.0

Enhancements

• Add tvos as a new platform.
  Boris Bügling
  Xcodeproj#301
• Allow accessing the new Xcode 7's Clang code coverage setting on XCSchemes
  ("Gather Code Coverage" checkbox).
  Olivier Halligon
  #307
• Adds Xcodeproj::XCScheme#save! to save in place when
  the XCScheme object was initialized from an existing file.
  Olivier Halligon
  #308

Bug Fixes

• Allow opening and saving projects that have circular target dependencies.
  Samuel Giddins
  CocoaPods#4229
• Fix the generation of deterministic UUIDs for .xcdatamodeld bundles.
  Samuel Giddins
  CocoaPods#4187