This reverts 2069496a for
gimpmeasuretool.c, we can't use gimp_display_shell_get_line_status()
here because the angle to show is *not* the angle as shown in the
paint tools (between x1,y1 and x2,y2), it is determined by a possible
third point.

Also, the info window and the statusbar were using different
coordintates to detemine the line length. This would have been easily
fixable, but the wrong angle wasn't.