function findLineIntersections(line, crossCheckLines) {
        return _(crossCheckLines).map(function(crossCheckLine) {
            return line.intersection(crossCheckLine);
        }).compact().value();
    }
Utility function to collect all intersection poinst of a single
line against group of other lines.
@param {g.line} line where to find points
@param {g.line[]} crossCheckLines lines to cross
@return {g.point[]} list of intersection points