Add PolylinePoint override to Draw.Line

It would be convenient to be able to call Draw.Line with two PolylinePoints as arguments.

My use case is that I already construct a PolylinePath to store Points/Colors/etc and generally draw them with Draw.PolylinePath, but in cases where it's clear that visual artifacts (see this post) would occur I switch to consecutive Draw.Line calls instead, because there is currently no support for Volumetric Polylines.

So Instead of this:

if ( usePolyline ) {
    Draw.Polyline( path, 1 );
} else {
    for ( int i = 0; i < path.Count-1; ++i ) {
        Draw.Line( path[i].point, path[i+1].point, 
            path[i].thickness, path[i].color, path[i+1].color );
    }
}

I'd do this:

if ( usePolyline ) {
    Draw.Polyline( path, 1 );
} else {
    for ( int i = 0; i < path.Count-1; ++i ) {
        Draw.Line( path[i], path[i+1].point );
    }
}