fix town generator placement of lamps in front of doors.  if doors are
set properly in the template, a single block will be ignored for
lamp-post positioning (might still have issues with double doors).
..
fix up loading of template images in directories in structure packs. 
More fixing of lamp-post generation in front of house doors.
fix mayoral mannor missing the top of its roof =\ (and add some random
loot to the chests)