Split json from main index.{html,js} files

A new API is introduced (/api/event/list/?format=json), and the index page is changed so it uses the API to retrieve events data. During events data retrieval an animated indicator is shown, and after receiving the data, the map is created and populated.
whoa!  forgot about this one

@ialja @sparkica @gandalfar @ercchy what do you guys suggest we do if the events data can't be retrieved and an error occurs?