function Average2d( mergedElements ) {

	// Average2d inherits from abstract strategy "StableMerge2d".

	StableMerge2d.call( this, mergedElements );

	this.strategyType = "Average2d";

}
Average2d, can be initialized by StrategyFactory directly.
MergeStrategy for MergedLayer when apply Average operation to 2d TensorSpace layers.

For example:
```javascript
let conv1d1 = new TSP.layers.Conv1d( { ...config } );
let conv1d2 = new TSP.layers.Conv1d( { ...config } );
let averageLayer = TSP.layers.Average( [ conv1d1, conv1d2 ], { ...config } );
```
In this example, the merged layer "averageLayer" apply merge strategy "Average2d".

@param mergedElements, array of TensorSpace layers. (layerList.length > 0)
@constructor