| Parameters: id | {String} a unique id of the popup. If null is passed an |
| identifier will be automatically generated. lonlat | {OpenLayers.LonLat} a longitude and latitude pair. The position on the map the popup will be |
| shown. contentSize | {OpenLayers.Size} a width/height pair size of the |
| content. contentHTML | {String} the HTML content to be displayed inside |
| the popup. anchor | {Object} object to anchor the popup too. closeBox - {Boolean} whether to display a close box inside the popup. |
| closeBoxCallback | {Function} Function to be called on closeBox click. |