caltechlibrary/eprints2bags: Version 1.5.0

Main changes in this release: * `eprints2bags` now determines which derived files to ignore for a given record by looking at the `` element for each `` listed in the `` element of a record , and checking if the relationship is `isVolatileVersionOf`. This makes it possible to ignore thumbnail images no matter what format or file name they have. * `eprints2bags` also now stores user login & password information on a per-server basis, instead of (as previously) using a single login & password for all servers. * Some newly-discovered bugs fixed. The file [CHANGES](https://github.com/caltechlibrary/eprints2bags/blob/master/CHANGES.md) contains a more complete change log that includes information about previous releases.