Serializers for objects.
Events are now numbered during import according to their order in CSV file.
Separate endpoints for different object classes.
Quick and dirty implementation of event program.
Display event category name.
Removed placeholder for empty category name.
Show placeholder text while loading data from server.
Changed verbose names for consistency.
Reduced number of AJAX calls.
Navbar with list of categories.
Filtering by category.
Hide blocks without search results.
Filter by part of the name.
Navbar now updated with selected category.
Timezone-aware loading of events.
Merge branch 'develop' of https://github.com/lensvol/slowclap into develop

Conflicts:
	slowclap/performances/management/commands/load_events_csv.py