GUI: fixed some add widgets

- Fixed already added widgets for vo ext sources and required attributes.
- Fixes for Group settings tab (display notice in drop-down if group is
  without members, source format, no changes widget optimization).
Merge pull request #170 from zlamalp/addFix

GUI: fixed some add widgets
GUI: logout from application form gui

- Added logout link to menu in application form.
- When form is submitted, but not stored (hard error),
  allow users to get back to app form without losing
  what they already filled in.
- Code simplification in logout widget.
- Clear shibboleth cookies method is now in Utils.
- Fixed "Go to perun web" button align on logout widget.
- Prevent accidental close of error reporting widgets created
  by json calls when clicking outside of the box. User must select
  desired action by click on button. This ensures, that user will be
  able to read error message.
- Source format.
Merge pull request #171 from zlamalp/logout

GUI: logout from application form gui