Add Line.getDistance() and use it in Curve.getOverlaps()

[iconexperience]

Added a static function getDistance() to line, that simply calls Line.getSignedDistance() and returns the absolute value. This makes the Line API a bit more symmetrical, which already has the mathod getDistance for the Line prototype.

In Curve.getOverlaps() we create a new instance of Line and at least one instance of Point to check if the two curves are overlapping lines. This is done for each pair of curves and the result is false in the vast majority of cases. Since this generates quite a lot of garbage for little effect, so I though it would be nice to implement a way that does the same without producing garbage. Also, the new code is smaller when minified, so this compensates a little bit for the extra code in Line.

[lehni]

Yes this makes a lot of sense. Thanks for spotting! We may want to use this approach in other parts too, e.g. in the code that calculates strokeBounds...