Feature request: Export map object to window

[loretoparisi]

This issue is related to https://github.com/rochacbruno/Flask-GoogleMaps/issues/27

function initialize_{{gmap.varname}}() {
               var {{gmap.varname}} = new google.maps.Map(
                         document.getElementById('{{gmap.identifier}}') )
       //...

Please add an option to export the var {{gmap.varname}} as a window var like

var {{gmap.varname}} = new google.maps.Map(
                         document.getElementById('{{gmap.identifier}}') )
window[{{gmap.varname}}]={{gmap.varname}}

In this way it will be possible to add markers from the page like

var marker = new google.maps.Marker({
    position: myLatlng,
    title:"Hello World!"
});

// To add the marker to the map, call setMap();
marker.setMap(window.map);

[rochacbruno]

Done! using a global variable. Thanks.