lineCrossesLineWithBoundary
fun lineCrossesLineWithBoundary(a1x: Double, a1y: Double, b1x: Double, b1y: Double, a2x: Double, a2y: Double, b2x: Double, b2y: Double): Boolean
uses orient method to compute whether two line segments cross; boundaries included - returning true for lines that terminate on each other.
e.g., (plus sign) + == true, and (capital 't') T == true
Use .lineCrossesLine to exclude lines that terminate on each other from the truth table