DTE - Distance to Edge

distanceToEdge - return distance to edge from specified (x,y) coordinates

Function Prototype:
float distanceToEdge (Edge *e, float x, float y);
distanceToEdge:
Input:
e		edge to which distance is to be computed
x		x-coordinate
y		y-coordinate

Author:  Dave Hale, Colorado School of Mines, 09/11/90