changes

README
	document new environment variables.

htmlmapdriver.html
	document new environment variables.

Graph_Clse.c
	remove writing newlines for type CLIENT, fixes bug in Internet Explorer.
	write ALT tag for type CLIENT.
	write NOHREF area for type CLIENT.

Polygn_abs.c
	remove successive points that are less than MINIMUM_DIST from previous.
	remove all ending points that are same as first point.
	remove polygon if bounding box size less that BBOX_MINIMUM.

Graph_Set.c
	accept environment parameters for min bounding box, min dist, &
	max points.

htmlmap.h
	set defaults for min bounding box, min dist & max points.

Text.c
	change strcpy() to custom copy, eliminate newlines in string.