Delete transients when he Keyring Eventbrite connection is removed.
Prefix transients with "eventbrite_". Can't use "eventbrite_api_" as its too many characters for the option name column.
Add the eventbrite_is_single() template tag. Also cleans up some Eventbrite_Query properties that were not being properly set.
Add ticket info from an Eventbrite iframe into event single views.