GUI: skip captcha for specific VOs

- Added property "vosToSkipCaptchaFor" to /etc/perun/perun-web-gui.properties
  which can contain list of VO's short names.

- GUI will skip catpcha request for such VOs and theirs group applications.
GUI: fixed mail notifications tab opening for different vos/groups

- Fixed hashCode() and equals() to check also groupId parameter.
GUI: check for similar users by commonName too on application form

- When checking for similar users, if displayName is empty, try to use
  common name to.
- For check when application is submitted also check displayName attribute,
  not just lastName.
Merge pull request #426 from zlamalp/captcha

GUI: multiple fixes to application form and notifications
GUI: fixed forgotten alert
Merge pull request #428 from zlamalp/similar

GUI: fixed forgotten alert
Delete member does not remove managers

Critical bugfix.
Delete member does not remove the user from managers of either VO and
groups in VO.

Manager role is granted to user (not member), therefore there is no need
to remove the role when membership in VO is lost.