Use dep to vendor things

vendor/github.com/faiface/glhf/util.go

@@ -0,0 +1,31 @@
+package glhf
+
+import "github.com/go-gl/gl/v3.3-core/gl"
+
+type binder struct {
+	restoreLoc uint32
+	bindFunc   func(uint32)
+
+	obj uint32
+
+	prev []uint32
+}
+
+func (b *binder) bind() *binder {
+	var prev int32
+	gl.GetIntegerv(b.restoreLoc, &prev)
+	b.prev = append(b.prev, uint32(prev))
+
+	if b.prev[len(b.prev)-1] != b.obj {
+		b.bindFunc(b.obj)
+	}
+	return b
+}
+
+func (b *binder) restore() *binder {
+	if b.prev[len(b.prev)-1] != b.obj {
+		b.bindFunc(b.prev[len(b.prev)-1])
+	}
+	b.prev = b.prev[:len(b.prev)-1]
+	return b
+}