Changes:
* Added typing [ and ] for first and last person.
* Added typing < (or comma) and > (or period) for previous and next person.
* Note: Command-arrows are still available but the new alternatives seem simpler to type.
* Corrected rollover help.
* Added a descent window to complement the pedigree window. This simply allows navigating descendants without changing the current person.
* The reference guide was updated to reflect these changes.
