Fixes #15268 - limit user taxonomies using my scopes

Fixes CVE-2016-4475

Fixes #15182 - limit user taxonomies in API (CVE-2016-4451)

Fixes #14546 - ability to restrict *_external_variables
Fixes #14535 - corrects permissions for smart class parameters

Fixes #15174 - make sure to return 404 when taxonomy not found

Fixes #14962 - support wildcard certs for proxy authentication

Refs #3809 - Turning on some rubocop cops

Fixes #6958 - supports in nested hostgroup in default PXE menu

The host group interface provides the opportunity to nest hostgroups,
with host groups inheriting parameters from parents.
when the default PXE menu is created however,
this nesting is not replicated, and only the final element...

Fixes #14369 - Removed default scope from host counter in taxonomies

Fixes #14252 - Redirecting to edit taxonomy page if no hosts to assign

fixes #13974 - remove nested arrays passed to AR finders

Passing a nested array to Active Record finder methods is deprecated in
Rails 4.2 and will be removed, they must be flattened first.