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
```
ctx.moveTo(x, y);
            if (width === 0 || height === 0) {
              ctx.lineTo(xw, yh);
            } else {
              ctx.lineTo(xw, y);
              ctx.lineTo(xw, yh);
              ctx.lineTo(x, yh);
            }
            ctx.closePath();
            break;
          case OPS.moveTo:
            x = args[j++];
            y = args[j++];
            ctx.moveTo(x, y);
            break;
          case OPS.lineTo:
            x = args[j++];
            y = args[j++];
            ctx.lineTo(x, y);
            break;
          case OPS.curveTo:
            x = args[j + 4];
            y = args[j + 5];
            ctx.bezierCurveTo(
              args[j],
              args[j + 1],
              args[j + 2],
              args[j + 3],
              x,
              y