Describes three collaborations

Traces and document the instantiation process of Flower and FlowerPhoto

Applies the Type Object pattern to class model

Documents five design pattern instances with annotations

Turns the Coordinate classes into value object classes

Add error and exception handling

Adds assert statements and assertion methods for preconditions and po…

…stconditions. Also implements an assertClassInvariants method

Introduces an abstract superclass 'AbstractCoordinate'

Adds a Coordinate interface to Wahlzeit and adjusts build.gradle with…

… new version for appEngine

Adjusts ModelMain by init FlowerPhotoFactory