return 10 superevents by default for superevents list resource, instead of 3.  Matches behavior of events list resource.

fixing issue with writing event logs when a preferred event is added to a superevent which previously didn't have a preferred event

handle changes to writeLog client function and clean up display name handling for tagging of event logs

changing format for event EMObservations and EMFootprint creation timestamps when these objects are converted to dicts

Adding custom pagination to superevents API to match events. It's bad, but will have to serve until we can redo the whole thing

updating event tag and event log tag resources to include more information than just a link to the detail page

adding superevent API urls - currently nesting them within the events API; should eventually be moved to a separate API app