The main grid outline in Pattern was asymmetric between the top/left

edges and the bottom/right ones. Fix it. (Also remove it from the
todo list in osx.m, where I had entered it in the assumption that it
was a bug in my new OS X port! Turns out it's an entirely platform-
independent bug.)

[originally from svn r5187]

osx.m

@@ -8,9 +8,6 @@
  *    think help is HTML round here anyway so perhaps we can work
  *    with what we already have.
  * 
- *  - Why are the right and bottom edges of the Pattern grid one
- *    pixel thinner than they should be?
- * 
  * Mac interface issues that possibly could be done better:
  * 
  *  - is there a better approach to frontend_default_colour?

pattern.c

@@ -903,7 +903,7 @@ static void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate,
          * Draw the grid outline.
          */
         draw_rect(fe, TOCOORD(ds->w, 0) - 1, TOCOORD(ds->h, 0) - 1,
-                  ds->w * TILE_SIZE + 2, ds->h * TILE_SIZE + 2,
+                  ds->w * TILE_SIZE + 3, ds->h * TILE_SIZE + 3,
                   COL_GRID);
 
         ds->started = TRUE;