Fix timezone-dependent test failures

Put a space before the timezone in show output

Display all-day events by civil date, not instant

Unify sexp output on sexp_of_t

Agenda: C-u r prompts for new date range

update icalendar

Add VALARM support: alarms subcommand, notification daemon, and tests

Fix find/replace rot in calendar_dir docs and naming

Fix timezone-dependent test failures

Put a space before the timezone in show output