First Draft

If everything works correctly then this will be the main way of saving
XML data.  Data is only written when Form1 is closed, and the entire XML
file will be rewritten instead of being editted each time.  During game
time only the starmap, agent etc objects will be manipulated.

Additionally, starmap no longer holds agents at home: all agent data is
stored in agents.
Stable Release...  kinda

Fixed most bugs, including a particularly persistent one caused by
loading starmap before playerinfo.  Load order should always be:
playerinfo, agents, starmap.

Seems to have a problem in displayStarmap() still, not sure what.