Specs: make sure all layout/paint/hitTest APIs are relative to the right coordinate space

sky/examples/style/hex-layout.sky

 #!mojo mojo:sky
 <import src="sky:core" as="sky"/>
 <script>
  class BeehiveLayoutManager extends sky.LayoutManager {
    function layout(width, height) {
      if (width == null)
        width = this.getIntrinsicWidth().value;
      let autoHeight = false;
      if (height == null) {
        height = 0;
@@ skipping 78 matching lines @@
      let cellCount = this.node.getProperty('beehive-count');
      let cellDim = width / cellCount;
      let children = this.walkChildren();
      let loop = children.next();
      while (!loop.done) {
        let child = loop.value;
        if (child.needsPaint) {
          canvas.save();
          try {
            canvas.beginPath();
-           canvas.moveTo(child.x, child.y + cellDim/4);
-           canvas.lineTo(child.x + cellDim/2, child.y);
-           canvas.lineTo(child.x + cellDim, child.y + cellDim/4);
-           canvas.lineTo(child.x + cellDim, child.y + 3*cellDim/4);
-           canvas.lineTo(child.x + cellDim/2, child.y + cellDim);
-           canvas.moveTo(child.x, child.y + 3*cellDim/4);
+           canvas.translate(child.x, child.y);
+           canvas.moveTo(0, cellDim/4);
+           canvas.lineTo(cellDim/2, 0);
+           canvas.lineTo(cellDim, cellDim/4);
+           canvas.lineTo(cellDim, 3*cellDim/4);
+           canvas.lineTo(cellDim/2, cellDim);
+           canvas.moveTo(0, 3*cellDim/4);
            canvas.closePath();
            canvas.clip();
            child.paint(canvas);
          } finally {
            canvas.restore();
          }
        }
        loop = children.next();
      }
    }
@@ skipping 11 matching lines @@
      return false;
    }
    function hitTest(x, y) {
      let cellCount = this.node.getProperty('beehive-count');
      let cellDim = width / cellCount;
      let children = this.walkChildren();
      let loop = children.next();
      while (!loop.done) {
        let child = loop.value;
        if (this.inHex(child.x, child.y, child.width, child.height, x, y))
-         return child.layoutManager.hitText(x, y);
+         return child.layoutManager.hitTest(x-child.x, y-child.y);
        loop = children.next();
      }
      return this.node;
    }
  }
  sky.registerLayoutManager('beehive', BeehiveLayoutManager);
  let BeehiveCountStyleValueType = new StyleValueType();
  BeehiveCountStyleValueType.addParser((tokens) => {
    let token = tokens.next();
    if (token.done)
@@ skipping 20 matching lines @@
  div { display: beehive; beehive-count: 3; }
 </style>
 <div>
  <t>Hello</t>
  <t>World</t>
  <t>How</t>
  <t>Are</t>
  <t>You</t>
  <t>Today?</t>
 </div>