Fixes #12827 - deconstantize resource only when needed

Fixes #12806 - adding merge_default to attr_accessible in lookup_key

Fixes #12799 - Add uuid to Compute Resource attr_accessible

Fixes #12180 - lookup_value presence validation moved from lookup_key

Global parameters can have empty values so smart variables that are also global should be allowed to accept empty values too.
The validation on lookup_value to make sure it isn't empty is in the LookupKey class therefore affecting both VariableLookupKey and PuppetClassLookupKey....

fixes #11862 - validating that casted hash is valid

Catch parse errors correctly under Ruby 1.9.3, and ensure the uncasted
value is displayed back in the UI if it fails to parse.

Fixes #12278 - make sure permission set is uniq for role

If default user has two or more filters with same permission (valid
setup), the verification of found collection failed. This patch
make the list uniq and the check correctly verifies whether all
permissions were found.

Fixes #12698 - Insufficient URL validation Smart Proxy and Medium.

Problem: The regex that validates smart proxies URLs only matches
'beginning of text'. This allows us to add just \n after a valid URL and
put anything after it. For instance, javascript:alert('hacked'). I...

Fixes #12659 - Fixed "inherit" behavior

Non-inherited attributes are now sent in the form data.

Fixes #12618 - Now calls for compute attributes are explicit.

Prevents compute attributes from being overwritten unconditionally from
the hostgroup's compute profile.

Fixes #12752 - Host and hostgroup clone should copy smart class parameters overrides