display mail version  too
take get_db_paths function out of class
Reset registration error and input widgets.

The registration widgets are cleared if the user goes back to the
provider selection page.

[Closes #4742]
Merge remote-tracking branch 'ivan-github/bug/4742_reset-registration-page-error' into develop
pep8
add repair mailbox utility
add changes file
Merge remote-tracking branch 'refs/remotes/kali/feature/repair-mailbox' into develop
Refactor provider_bootstrapper out of mainwindow
Add changes file