cherry-pick saily first location indexer change, commit id 6ebf8aab654ca0ff75a2e6549b5a2799da8f0f43
Better IEventLocation indexer

It's possible to create events withouth IEventLocation behavior. So the previous adapter would raise a TypeError. AttributeError would be the correct exception for a catalog index to raise if a object does not provide a value.
cherry-pick timo^s first change regarding the removal of simple_publication_workflow from test layer. commit id: 9b7e19aab7ae389466dbe27926724df749c63e47
new version of icalendar
Set workflow to simple_publication_workflow for base_setup.py tests. This fixes the test failures that have been introduced by the removal of the workflow set in the test fixture.
backport timo^s workflow setting changes from master