[GRASS5] current position

[Huidae Cho]

According to lib/raster/protocol.c ALL R_*_(abs|rel) function should update
cur_x and cur_y in the display driver, but I found some routines don't:

R_polydots_*:	updated to the last point
R_polyline_*:	updated to the last point
R_polygon_*:	NOT updated => should be the first/last point
R_box_*:	NOT updated => should be x2, y2

If R_polygon_*/R_box_* update the current position, is there any side effect?

Thanks.
Huidae Cho