Add desk components 466-485 and icon.Bomb

Twenty pieces of a retro desktop: Desktop, DesktopIcon, Taskbar,
StartMenu, AppWindow, Calculator, Notepad, Minesweeper, ControlPanel,
TrayIcons, ShutdownScreen, BootScreen, Screensaver, Snake, Dock,
RunDialog, DiskDefrag, WallpaperPicker, ClipboardPanel and LockScreen.

The calculator really adds up and calls division by zero GAME OVER;
Minesweeper and Snake are playable, first click always safe; START
cascades its submenus without moving the rows already open; windows
drag by whole dots; the screensaver's logo changes color at each wall
and sparkles in a corner; the defragmenter is oddly soothing. Clocks
that step back hold at zero, and typed or copied text never reaches
the log.

icon.Bomb is the new 12x12 mine.

icon/icon.go

@@ -31,7 +31,7 @@ var All = []Named{
 	{"heart", Heart}, {"heart-empty", HeartEmpty}, {"star", Star}, {"star-empty", StarEmpty},
 	{"sparkle", Sparkle}, {"volume", Volume}, {"mute", Mute}, {"play", Play},
 	{"pause", Pause}, {"stop", Stop}, {"next", Next}, {"prev", Prev},
-	{"coin", Coin}, {"gem", Gem}, {"crystal", Crystal}, {"potion", Potion}, {"sword", Sword},
+	{"coin", Coin}, {"gem", Gem}, {"crystal", Crystal}, {"bomb", Bomb}, {"potion", Potion}, {"sword", Sword},
 	{"shield", Shield}, {"chest", Chest}, {"crown", Crown}, {"trophy", Trophy},
 	{"skull", Skull}, {"scroll", Scroll}, {"flame", Flame}, {"drop", Drop},
 	{"leaf", Leaf}, {"flower", Flower}, {"sun", Sun}, {"moon", Moon},

icon/items.go

@@ -43,6 +43,19 @@ var (
 		...e#lsse...
 		....e#se....
 		.....ee.....`)
+	Bomb = pixel.MustSprite(`
+		......#.#...
+		.......#....
+		......e.....
+		.....e......
+		...eeeee....
+		..ekkkkke...
+		.ekllkkkke..
+		.eklkkkkke..
+		.ekkkkkkke..
+		..ekkkkke...
+		...eeeee....
+		............`)
 	Potion = pixel.MustSprite(`
 		....eeee....
 		....eeee....