def add_file_reference_with_uuid(file_ref, uuid, avoid_duplicates = false)
      if avoid_duplicates && existing = build_file(file_ref)
        existing
      else
        build_file = project.new_with_uuid(PBXBuildFile, uuid)
        build_file.file_ref = file_ref
        files.insert(0, build_file)
        build_file
      end
    end
def add_file_reference_with_uuid(file_ref, uuid, avoid_duplicates = false)
      if avoid_duplicates && existing = build_file(file_ref)
        existing
      else
        build_file = project.new_with_uuid(PBXBuildFile, uuid)
        build_file.file_ref = file_ref
        files.insert(0, build_file)
        build_file
      end
    end
Adds the file reference with given UUID.

 @param [String] uuid UUID of the object.