Minor changes in Section 5

For better readability a few changes are proposed on the first paragraph:

From "In addition to the generic elements outlined in Chapter 4," to "In addition to the generic core elements outlined in Chapter 4,"

Add at the end of the paragraph: "Relationships and relationship connectors do not belong to any specific layer or aspect as defined in the ArchiMate Full Framework, and in many situations link elements from different layers and/or aspects."