make sure drawable matrix and silhouette for mouse touching

RenderWebGL methods that test drawable touching should call
updateMatrix and updateSilhouette before calling drwaable.isTouching.
These methods are called by RenderWebGL instead of isTouching because
isTouching can be called repeatedly in quick succession. Calling update
methods in isTouching would waste a lot of cycles.

Author: mzgoddard

src/RenderWebGL.js

@@ -930,6 +930,9 @@ class RenderWebGL extends EventEmitter {
         const bounds = this.clientSpaceToScratchBounds(centerX, centerY, touchWidth, touchHeight);
         const worldPos = twgl.v3.create();
 
+        drawable.updateMatrix();
+        drawable.skin.updateSilhouette();
+
         for (worldPos[1] = bounds.bottom; worldPos[1] <= bounds.top; worldPos[1]++) {
             for (worldPos[0] = bounds.left; worldPos[0] <= bounds.right; worldPos[0]++) {
                 if (drawable.isTouching(worldPos)) {