fix: this._layer -> this.options.layer

[mashkovd]

When initialize - this._layer = this.options.layer || new L.LayerGroup(). Then bool(this._layer) always is True(options.url is never use) If options.layer is null. It's bug

[andrew-lis]

Thanks! it took me an hour to figure out why the newest version ain't workin'! I've checked the code and figured out that there's no way it gonna work!

My temporary hack:

        this.map.addControl(searchControl);
        searchControl._layer = null; // reset layer after initialization

[hrzhao]

It was same gay only modify this line and raise this bug. look #285

[stefanocudini]

solver from version 3.0.0 published in npm