DrawTool support transform coordinate

[deyihu]

fix maptalks/issues#698
fix #1359

        const drawTool = new maptalks.DrawTool({
            mode: "Point",
            once: true,
            transformCoordinate: (coordinate, mapEvent) => {
                const result = groupGLLayer.identify(coordinate);
                if (result.length) {
                    return new maptalks.Coordinate(result[0].coordinate);
                }
            }
        })
            .addTo(map)
            .disable();

[fuzhenn]

需等待测试通过

[deyihu]

已经通过