update entries with MNRAS.tmp bibcodes

[lauralwatkins]

MNRAS typically issues a temporary identifier before assigning a final reference, with bibcodes that look something like this: 2016MNRAS.tmp..123A.

Often, when I run adsbibdesk in update mode, it finds that an arXiv entry now has a temporary MNRAS ID and so it updates to that new ID, but there's currently no way to check for and update these temporary MNRAS IDs to their final IDs, along with associated final reference details. A DOI is issued by MNRAS along with the temporary ID, but not the final year and month of publication, the volume number or the pages.

I can see two possible ways to deal with this:

1. when checking for arXiv updates, ignore the update if it is a temporary MNRAS bibcode.
2. keep the existing behaviour (where arXiv bibcodes get updates to MNRAS.tmp bibcodes), but add an extra check to find+update MNRAS.tmp bibcodes.

I don't know which would be easier to implement/work better.