Performance considerations

[ghost]

With this guide in mind, I'll pin up some considerations for this library that may improve performances:

• 1. Use ChangeDetectionStrategy.OnPush for comparing @input by reference and not by object content?
• 2. According to point 1. trigger layer.draw() only when config actually changes
  

  ngx-konva/projects/ngx-konva/src/lib/components/ko-layer.component.ts

  Line 29 in bb94638

  this._config = c;

• 3. Considering layer.batchDraw()? May be outdated with konva@9
• 4. According to this, it may be useful set listening(false) by default and enforce the use of listening directives to enable only explicitely shape (or layer) listening.
  

  ngx-konva/projects/ngx-konva/src/lib/components/ko-shape.component.ts

  Line 51 in bb94638

  this.shape = new (koShapeTypesMap[this.selector] as any)(this._config as any);

• 5. As for point 4, disable by default stroke shadows.
• 6. Automatically debouncing layer drawing?
• 7. Enforce trackBy function for shapes *ngFor in documentation?
• 8. Check considerations on Konva.pixelRatio = 1 (automatically on Retina displays?)
• 9. Switch off perfect drawing by default?
• 10. Add shape caching for each component?