Support for displaying communications: multi-location events.

[francamps]

Events of communication can be described as events that happen simultaneously in two or more locations (if there are more than two participants). We suggest to call this coevents to refer to this property.

• coevents data format should accommodate for multiple sets of coordinates.
• coevents are a function of time, similarly to how events are.
• coevents should be displayed distinctively on the timeline and on the map
• coevents should be capable of being grouped by category, and being as well as containing tags.
• Like the rest of the application, coevents will be rendered vector graphics, able of being styled, with properties such as stroke and fil
• coevents could contain additional information to be displayed on click, in the CardStack component, similar to how events do.
• coevents will be fetched together with the rest of the domain.
• Their format will be validated in the reducer together with the rest of the domain.

[breezykermo]

@ebefarooqui something interesting to think about in terms of associations, perhaps?