index.html example passes invalid parameters to leaflet CircleMarker constructor

[matt-glover]

Leaflet expects a point and an options hash as parameters to the CircleMarker class. Currently the code provides this:

var circle = new L.CircleMarker(start, 2, circleOptions);

It should instead provide this:

var circle = new L.CircleMarker(start, circleOptions);

[springmeyer]

closed by closing #7