Add data components 151-175; clear MyGo row highlights

Lists, tables, trees, grids, inventories and records in data/.
Outline and GridView build on ui.List: ui.Outline strokes its arrows
and ui.GridView spaces and tints items. The pixel theme keeps MyGo's
row highlights clear so scrolled rows stay on whole dots; off lists
take a veil against the wheel. Adds Canvas.Silhouette, SwitchOptions
Label and exports Rarity.Slot.

data/cardgrid.go

@@ -0,0 +1,23 @@
+package data
+
+import (
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/layout"
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+type CardGridOptions struct {
+	// MinWidth is a card's least dots; zero means 96.
+	MinWidth int
+}
+
+// CardGrid fits as many card columns as width allows.
+func CardGrid(c *ui.Context, n int, o CardGridOptions, card func(i int)) *ui.Element {
+	mw := pixel.Or("CardGrid MinWidth", o.MinWidth, 96)
+	box := ui.Box(c).FillWidth()
+	w, check := pixel.WrapWidth(c, box)
+	return box.Draw(func(p *ui.Painter, r ui.Rect) { check(r) }).Children(func() {
+		layout.Grid(c, n, layout.GridOptions{Columns: max(1, w/mw), Pad: 2}, card)
+	})
+}