bool
    LineIntersectionFactorXZ 
            (        
)
    
    Returns the intersection factors for line 1 and line 2. 
    The intersection factors is a distance along the line start - end where the other line intersects it.
intersectionPoint = start1 + factor1 * (end1-start1) 
 intersectionPoint2 = start2 + factor2 * (end2-start2) 
 Lines are treated as infinite.
false is returned if the lines are parallel and true if they are not. Only the XZ coordinates are used.