Added a thin black border above and below the projections.

- solidify/style.h (PROJECTION_BORDER): number of pixels to leave dark above
  and below the face
- solidify/level.c (draw_xz, draw_zy, level): increase projection z size by
  twice the border width
- solidify/level.c (draw_xz, draw_zy): offset z coordinates by the border

solidify/style.h

@@ -26,6 +26,7 @@ extern GdkGC *gc_osd;
 #define	SLOWEST_ROT		3	/* thrice the half-diagonal */
 #define	FASTEST_ROT		2	/* one pixel in distance of 2 pixels */
 #define	DIST_STEPS		5	/* fastest shift is 5 px/wheel step */
+#define	PROJECTION_BORDER	2	/* pixels around projections */
 
 
 void init_style(GdkDrawable *da);