Add support for secondary author in 100 field (w/ appropriate $e).

- Improves RDA support, but should not break existing behavior.

import/marc.properties

@@ -46,10 +46,10 @@ author                = custom, getAuthorsFilteredByRelator(100abcd:700abcd,100,
 author_variant        = custom, getAuthorInitialsFilteredByRelator(100a:700a,100,firstAuthorRoles)
 author_fuller         = custom, getAuthorsFilteredByRelator(100q:700q,100,firstAuthorRoles)
 author_role           = custom, getRelatorsFilteredByRelator(100abcd:700abcd,100,firstAuthorRoles)
-author2               = custom, getAuthorsFilteredByRelator(700abcd,700,secondAuthorRoles)
-author2_variant       = custom, getAuthorInitialsFilteredByRelator(700a,700,secondAuthorRoles)
-author2_fuller        = custom, getAuthorsFilteredByRelator(700q,700,secondAuthorRoles)
-author2_role          = custom, getRelatorsFilteredByRelator(700abcd,700,secondAuthorRoles)
+author2               = custom, getAuthorsFilteredByRelator(100abcd:700abcd,700,secondAuthorRoles)
+author2_variant       = custom, getAuthorInitialsFilteredByRelator(100a:700a,700,secondAuthorRoles)
+author2_fuller        = custom, getAuthorsFilteredByRelator(100q:700q,700,secondAuthorRoles)
+author2_role          = custom, getRelatorsFilteredByRelator(100abcd:700abcd,700,secondAuthorRoles)
 author_corporate      = custom, getAuthorsFilteredByRelator(110ab:111abc:710ab:711ab,110:111:710:711,firstAuthorRoles|secondAuthorRoles)
 author_corporate_role = custom, getRelatorsFilteredByRelator(110ab:111abc:710ab:711ab,110:111:710:711,firstAuthorRoles|secondAuthorRoles)
 author_sort           = custom, getFirstAuthorFilteredByRelator(100abcd:110ab:111abc:700abcd,100:110:111:700,firstAuthorRoles)