Release 4.2.0

Changes:
- Added parameters to configure ALLOWED_HOSTS in settings_local.y and
  ServerAlias in apache, no longer requiring these values to be the fqdn
- Fixed removal of vhost conf file
- Added support for secure cookies

Change-Id: Icba9aad7c21da0ae6ec77a25bccd6018211e8632
Merge "Release 4.2.0" into stable/icehouse