Do some pep8 fixes.
Stop the services if the selected provider is changed.

Store the last 2 indexes on a deque and improve the 'select previous
provider' action.
Ask for services stop when the wizard is needed.
Add changes file. Related to #4704.
Merge remote-tracking branch 'refs/remotes/ivan/feature/single-provider-at-a-time' into develop
Add issues fixed on the changes file.
Merge remote-tracking branch 'refs/remotes/ivan/feature/update-changes-file' into develop
Use same user/password restrictions as in the webapp.

- no uppercase allowed in usernames,
- password length min to 8

Closes #5894.
Merge remote-tracking branch 'refs/remotes/ivan/bug/use-same-user-and-pass-restrictions-as-in-the-webapp' into develop
Default to No if ESC pressed on 'install helper files'.

Closes #5819.
Merge remote-tracking branch 'refs/remotes/ivan/bug/esc-default-to-no' into develop
moved provider selection popup menu to be at the top of the main window
Merge remote-tracking branch 'refs/remotes/elijah/feature/provider-on-top' into develop
Fold in changes and update relnotes
Merge branch 'release-0.6.1'
Merge tag '0.6.1' into deb-0.6.1

Tag leap.bitmask version 0.6.1
update changelog to 0.6.1 final
freeze debian version