Test updates

[patrickmj]

A couple small bugfixes, and a new feature to change the handle server to make the linkback work are in play here, so it's worth a quick walkthrough to check that everything still works as expected

• the new language about setting the handle server makes sense
• the handle server setting works (I'll email details of sites to look at separately, since the person who reported issues didn't want to put the URL out in public on GitHub)
• the link back on the display works for two different DSpace installations that have different handle servers
• upgrade process is involved, too

Develop branch of DspaceConnector, Master of Omeka S

UPDATE: hold this. just spotted something new

[patrickmj]

Welp. Looks like the differences were errors in MARS, so this will all be rolled back.