UCM — Create a section for the graphical guidelines

In document Beta 1, section 9 contains several small sections that describe the graphical guidelines for the creation of graphical, informal representation of UCM models. These sections have been removed during by issue #37. A new section should be added at the end of the document to explain the non-normative graphical guidelines

Create a section for the graphical guidelines

Create a new section describing the graphical guidelines and update diagrams according to these guidelines.