Check job in docworks before showing import button

So that you can't 'import' it when it's been acquitted.
change the import method to not leave cruft behind when it fails.
Merge pull request #359 from nla/js-isolate-dwImport

change the import method to not leave cruft behind when it fails.
Merge pull request #358 from nla/hr-restrict-import-btn

Check job in docworks before showing import button
Merge remote-tracking branch 'origin/master' into dcm-mig-2