The class names of all objects created by functions in pixelclasser
now start with
pixel_. The internal structure did not change, however,
so it is safe to change the class of any object created with version 1.0
into the new classes with
class(my_object) <- "new_class_name".
summary() (S3) were added for the
classes created by
create_class() were replaced by
pixel_class(), to make the name of the
object constructors equal to the class name.