Configuration:
- PDF.js version: 2.0.550

Steps to reproduce the problem:
1. Render document in SVG mode `renderMode="svg"`

What is the expected behavior? (add screenshot)
Rendering annotations same way as they rendered on canvas

What went wrong? (add screenshot)
```
Warning: Unimplemented operator beginAnnotations
Warning: Unimplemented operator endAnnotations
```
imgData,
      scaleX,
      skewX = 0,
      skewY = 0,
      scaleY,
      positions
    ) {
      if (!this.contentVisible) {
        return;
      }
      const ctx = this.ctx;
      ctx.save();
      const currentTransform = ctx.mozCurrentTransform;
      ctx.transform(scaleX, skewX, skewY, scaleY, 0, 0);
      const mask = this._createMaskCanvas(imgData);
      ctx.setTransform(1, 0, 0, 1, 0, 0);
      for (let i = 0, ii = positions.length; i < ii; i += 2) {
        const trans = Util.transform(currentTransform, [
          scaleX,
          skewX,
          skewY,