Add robust error handling to data load

[flibbertigibbet]

Protect against app crash when loading data from the server. Currently, the app crashes when encountering an unpublished destination associated with an event with a foreign key error.

See: azavea/cac-tripplanner#1044

If this or some similar data or parsing issue is encountered, catch and log the error, skip the record, and proceed to process the rest. Consider showing the user a Toast message or other feedback if the entire fetch or parse failed.