Indicate how event results are sorted

[RobDolin]

When browsing to the homepage, it is not clear what order event results are returned in.

It would be useful to see if these are sorted by proximity, date, alphabetically, etc. and then to have the ability to change the sort order.

[loganbyers]

I would be willing to tackle this but it might be better to wait until #17 is complete. Sorting by date would be much easier if events had a date field.

FWIW the current sort is direct from the database, so oldest entries are first.

I would add the following sorts:

• Date of Event (ascending only?; Default?)
• Date created, to see newest additions
• Proximity to search address
• Group by event type, maybe each has a header or graphic indicator
• Group by organization
• Alphabetical by event title

It should be as simple as doing a QuerySet.order_by() in MapView.