Fixes #4441 - Overriden link_to method should be public, not protected
fixes #4394 - generate class method on AR collections to retrieve used_taxonomy_ids
New permissions model

Contains:
* Usergroup roles support
* Usergroup nesting (with cycle prevention)
* Caching of user roles and membership
* Admin flag can be assigned to usergroup
* Role filters for better granularity
* Migration of old DB to new permission model
API v2 migrated to new permissions model

API v1 migration to new permissions model

Set authorizer filter for controllers

Various typo errors on API controllers corrected

Remove role validator to make migration script pass

Authorizer in application controller

@authorizer goes in application_controller and it is called from the
views, since it's a helper method. This saves us from having an
after_filter or @authorizer defined everywhere.
However I believe this might be a security risk and Authorizer should
be a singleton class.

Use @smart_proxies over @proxies for consistency
Seed now creates all roles and permissions

Also some other refactorings and cleanups
Remove find_os, leftovers from ares's refactor

DB agnostic backups before permissions migration
Fixes and tests
GC deferred threshold for tests

This tweak allows us to save some time when running the test suite.
https://37signals.com/svn/posts/2742-the-road-to-faster-tests#all_comments
explains it better.

It went from 11m. 12s, to 8m, 50s, averaging two test runs.

Functional tests adapted to new permission model

Added oj to Gemfile to fix multi_json problem

fix for https://github.com/intridea/multi_json/issues/86 , which raised
when running some tests
More fixes and tests
Import task for mysql/pg dumps
API for plugins adapted to new permissions
move permission migration code into migration
Contains:

* DB agnostic backups task
* Split seeds file into separate files
v2api - permissions index and show

rbac_v2api - basic v2 api working

rbac_v2api - corrected apipie
Taxonomy support in filters

Plus other fixes and tests
Clone roles

This feature allows users to clone roles easily. Roles are deeply cloned
using the gem 'deep_cloneable', so that the associations (permissions
    and filters) are cloned as well

Fix routes problem on clone role
Fix for several issues
Make host#edit use consistent field rules
Reviews
Adds deep cloneable dependency