Show conferences already without event time informations and location assignments

[sippsack]

Java Forum Stuttgart and Java Forum Nord decide timeslot and/or location assignments a few days after before the conference takes place. They first ask their attendees about there favourites and decide about the final schedule then.

DukeCon client should already show events without time and/or location assignments.

[sippsack]

I will provide a simple conference json with a few events but without times and locations.

[sippsack]

if all events have no time, the schedule view must be hidden/disappear.

If all events have no location assignments, the location filter could be hidden, too.