Added support for fill color layers.
Added support for radial gradient layer.
Throw an error when no layer could be created from the data provided.
Updated example.
Linear gradients are now also supported.
Linear gradients can now have a rotation angle.
return TYPE_GRADIENT.
Fixed mask example.
Added option of a html canvas as a layer.
Added example canvas as a mask layer.
Added possibility of adding an image object as a layer.
An entire canvas can now be added as a layer.
Added example of using a canvas as a layer.