def path_to(relative_filename, relative = false)
      if relative
        File.join(@name, relative_filename)
      else
        File.join(@path, relative_filename)
      end
    end
def path_to(relative_filename, relative = false)
      if relative
        File.join(@name, relative_filename)
      else
        File.join(@path, relative_filename)
      end
    end
Computes the absolute path to a file in an extracted package given its
 relative path. The argument +relative+ can be used to get the path
 relative to the course repository.

 Ex.
    <tt>pkg.path => '/var/lms/courses/MyCourse/'</tt>
    <tt>pkg.course_repository => '/var/lms/courses/'</tt>
    <tt>path_to('images/myimg.jpg') => '/var/lms/courses/MyCourse/images/myimg.jpg'</tt>
    <tt>path_to('images/myimg.jpg', true) => 'MyCourse/images/myimg.jpg'</tt>