Bibcheck: Adds chk_fix_affiliation_subfield plugin

* This plugin moves the subfields 100__u to 100__v and
  700__u to 700__v in the journals: APPB, AHEP, CPC, JCAP and NJP.

Signed-off-by: Martin Vesper <martin.vesper@cern.ch>
Merge pull request #21 from mvesper/bibcheck_fix_affiliation_subfields

Bibcheck: Adds chk_fix_affiliation_subfield plugin