code: func NewPointFromQuadkey(key int64, level int) *Point {
  	var x, y int64
  
  	var i uint
  	for i = 0; i < uint(level); i++ {
  		x |= (key & (1 << (2 * i))) >> i
  		y |= (key & (1 << (2*i + 1))) >> (i + 1)
  	}
  
  	lng, lat := scalarMercatorInverse(uint64(x), uint64(y), uint64(level))
  	return &Point{lng, lat}
  }
docs: // NewPointFromQuadkey creates a new point from a quadkey.
  // See http://msdn.microsoft.com/en-us/library/bb259689.aspx for more information
  // about this coordinate system.