title: How to remove a layerGroup in leaflet?
body: <p>it is easy to add a layerGroup to a leaflet map by simply calling     <code>layergroup.addTo(map)</code>.
  How I can I remove the whole <code>layergroup</code> from the map? I tried            <code>layergroup.eachLayer(function(layer) { map.removeLayer(layer);});</code>
  But, the map begins to behaviour weirdly. </p>