Add corporate author (110) to TPAC author pool

As requested in LP#1168186, here is a simple attempt to add corporate
authors to the author 'pool' in TPAC.

We may also want to consider adding 111 (meeting or conference as
main entry), but that isn't totally clear cut.

Signed-off-by: Dan Wells <dbw2@calvin.edu>
Signed-off-by: Mark Cooper <markchristophercooper@gmail.com>
Signed-off-by: Ben Shum <bshum@biblio.org>
LP1168186 - Add tag 111 and remove subfield 4 from author pool

Add meeting/conference main entry (111) to TPAC author pool.

Remove subfield 4 from the author data because the information contained
refers to relator and may not be helpful at this time.

Signed-off-by: Ben Shum <bshum@biblio.org>
Signed-off-by: Mark Cooper <markchristophercooper@gmail.com>