Make it configurable whether the first event displayed should be larger than subsequent with configurable horizontal spacing

This is, as #85, the solution from https://code.google.com/p/fullcalendar/issues/detail?id=218#c15, made configurable.

The difference from #85 is that this request also includes a configurable horizontal spacing between events. That means that *either* this or #85 should be pulled (should any of them be).