Function multiply

Multiplies start and end of line by point.x, point.y.

import { Lines } from 'https://unpkg.com/ixfx/dist/geometry.js'

// Line 1,1 -> 10,10
const l = Lines.fromNumbers(1, 1, 10, 10);
const ll = Lines.multiply(l, {x:2, y:3});
// Yields: 2,20 -> 3,30