Change poorly named 'date-pattern to 'time-pattern.
Change 'catch-false from macro to thunk wrapper.

Also, en passant, move docstring from body to docstring position.
Commit of nearly complete but broken data collection for reference.
Fix extraction of room and date.
Handle talks which have no link.

Talks with a link have another level of nesting for the anchor tag. Wrap
non-linked talks with a normal vector to handle this.
Fully extract and construct full information for talks.