Use dep to vendor things

vendor/github.com/faiface/pixel/pixelgl/util.go

@@ -0,0 +1,15 @@
+package pixelgl
+
+import (
+	"math"
+
+	"github.com/faiface/pixel"
+)
+
+func intBounds(bounds pixel.Rect) (x, y, w, h int) {
+	x0 := int(math.Floor(bounds.Min.X))
+	y0 := int(math.Floor(bounds.Min.Y))
+	x1 := int(math.Ceil(bounds.Max.X))
+	y1 := int(math.Ceil(bounds.Max.Y))
+	return x0, y0, x1 - x0, y1 - y0
+}