Bug fix & html tidy

This is virtually a complete rewrite of the module

Changes.
1. Generated code passes HTML5 validation (bug #1236995)
2. All styling done in themes CSS
3. Only items that are 'real' links look like links and respond to mouse clicks
4. Step mother/father are identified as such in the 'Parents' menu

The validation problem with the original code was that nested `<a..>` elements were generated in function print_pedigree_person_nav. I originally looked at using cascaded WT_Menus but although the result validated, the appearance wasn't very nice. Using getMenuAsList()  restored the look but reintroduced the validation problems.

The solution adopted here is to replace the nested `<a..>` elements with `<div>`'s styled to look like links and to use a bit of javascript to provide the onclick functionality.

The module has been restructured to replace the huge print_pedigree_person_nav() function with getParents() & getFamily(). In my view this provides a more logical structure whilst eliminating some global (within the module) variables.