Restore field editor’s value after reloading file browser

If user was creating a new file or folder and immediately started to type in the field editor, his changes were lost during reload (which would likely happen when updating SCM badge for the newly created item).
Add completion callback to installBundle:
Close bundle install sheet on error

Previously incase of error the sheet would keep showing effectively locking up the document window.

This is related to issue #85 although the reason why installing bundles fails for some users is still unanswered.