Progressive loader duplicates duration events that cross time blocks

[GoogleCodeExporter]

See https://groups.google.com/forum/#!msg/timemap-development/1lrYzurhuJs/

The issue is that the progressive loader works well for instant events, but it 
looks like it has some issues for duration events, especially long-running 
duration events. It is logical for the server-side service to return 
cross-block events for multiple requests. But it's hard for the progressive 
loader to check for duplicates, and the current implementation doesn't try. 

I think the best option here would be for the progressive loader to take an 
optional function to uniquely identify items, maybe defaulting to a hash of 
title + location + time (though in your case location is a lot of data, unless 
we use a real hash library like md5), and then filter out duplicates in a 
custom preload function.

Original issue reported on code.google.com by [email protected] on 24 Dec 2011 at 3:54