Fixes #11458 - Override inline for class parameters

This implements override inline for smart class parameters and smart
variables in host and hostgroup edit forms.
Global variable override inline will be done in a seperate PR.

Authors:
Ori Rabin <orrabin@redhat.com>...

Fixes #12461 - Compute profile is properly selected.

Fixes #11643 - [API] Add preview template to host

Fixes #11307 - Add host count to hostgroups

Fixes #12478 - don't update :attached_to if parsed :attached_to is nil

Fixes #12477 - remove duplicate ALT Linux logo

Fixes #12424 - Labels in chart legends are aligned to left

fixes #12342 - unsaved (new or cloned) hostgroups keep their puppetclasses

Unsaved hostgroups didn't respond correctly to individual_puppetclasses
because that method expects some objects to be saved in the DB. In case
of selecting a new environment, that lead to puppetclasses disappearing....

fixes #12194 - join fact tables multiple times for each search term

scoped_search usually generates a new inner join for each search term
when searching through a key/value table layout to correctly search for
hosts via multiple facts. Since the change to ext_method in 3f8e6c33, a...

Fixes #12457 - Use .exists? to check subnet exists on Rails 4

On app/models/subnet.rb, the method `self.import` uses `if
first(:conditions => attrs)`. It no longer is an alias for
`find(:first, *args)` but now it just fetches the first X
records (`first(X)`). `.exists?` is a suitable equivalent