Bug fix #191: Add rounded-corners detection to --unredir-if-possible

Add `bounding_shape` and `rounded_corners` as condition match target.
Deprecate --shadow-ignore-shaped. Add rounded-corners detection to
win_is_fullscreen(). Slightly modify win_rounded_corners() logic. Thanks
to tdryer for reporting. (#191)

compton.sample.conf

@@ -18,7 +18,6 @@ shadow-exclude = [
 	"_GTK_FRAME_EXTENTS@:c"
 ];
 # shadow-exclude = "n:e:Notification";
-shadow-ignore-shaped = false;
 # shadow-exclude-reg = "x10+0+0";
 # xinerama-shadow-crop = true;