Modify trunk CSS Styling documentation.
1. Mention that the style needs to be set in the Layer properties to the new CSS style - it is not assigned in the 'CSS Demo'.
2. Where necessary, split tables so that they are not more than one page long - else the bottom of the table is missing in the PDF documentation.
3. Possibly, add some information about anchoring labels.
4. Add a section for examples, and add an example where the markers' areas are proportional to an attribute value.
5. Some general editing.