#966 Indicate existing ISBN on new pubs

[Anonymous]

On the moderator approval screen for "Add New ..." publication entries, show a 'warning' (similar to what is already done for new authors, pseudonyms, etc.) next to the ISBN field if the ISBN already exists in the database.

This is the first thing I check when processing new entries and with newer editors often find cases where they are submitting a duplicate or should have used clone instead.

[Ahasuerus]

Implemented in:

biblio/adv_search_results.py 1.25
biblio/se.py 1.53
common/isbn.py 1.3
common/viewers.py 1.122

Installed in r2016-217 on 2016-12-28. Closing.

[Ahasuerus]

Part 2 - Fixed an Import/Export bug in common/viewers.py 1.124. Installed in r2016-219 on 2016-12-29. Keeping the FR closed.