Display job columns in search results (Adv search / Profile Listing)

After running a search, the set of columns should include (roughly) "Name", "Job Position", "Department", and "Line Manager". This is a bit ambiguous because each contact may have multiple jobs.

Some proposals raised:

1. Flag one job as primary. The result-listing would always display the primary. (This is a bit like how we handle phone/email.) There are some soft business rules on how to identify the primary (e.g. active positions are more important than inactive positions; paid positions are more important than unpaid positions; full-time is more important than part-time).

2. Concatenate data from each job into one cell. For example, the "Department" cell might say "Alice Exampleson; Bob Sampleman"; the "Department" cell might say "Accounting; Marketing".

3. In the result listing screen, display separate rows for each job position. This is a bit of a non-starter because our search system typically references rows by "contact_id" (which would not be unique if we had separate rows for job positions).

For implementation, we might:

1. Create a new "CRM_HRJob_BAO_Query" class, or...
2. Use a hook to inject new columns into the table, or...
3. ??