Fixes #13755 - allow reading of AR collections with safe mode enabled

Fixes #9553 - Remove workaround for older json version

We already use json 1.8, this workaround is no longer needed.

fixes #13409 - remove early initialisation of test DB

All models etc. referenced within the Rails environment startup,
including in initialisers should load without making any reference to
the database. This ensures when running `rake test` without a test DB...

fixes #12873 - update Rails to 4.1.14.1

maintain_test_schema! changed behaviour and now launches db:test:prepare
in the background, causing the environment to be loaded again. A check
in the initializer prevents this from happening recursively.

Ideally this call would be removed from the initializers and leave it to...

Refs #12911 - Fixing colon method calls

fixes #8874 - rework POT/PO updates for gettext 3's edit.po

3.1.13 adds an intermediate .edit.po file alongside each .po, which is meant
to be kept outside of SCM and updated by users, whereupon it's merged back into
the .po on the next rake gettext:find execution....

fixes #13168 - permit safemode templates read-only access to AR relations

Templates such as kickstart_networking_setup use relations of
Host::Managed to access network interfaces. Since Rails 4, these return
relation objects rather than arrays which being core Ruby, had permitted...

Fixes #13171: Prevent frozen array error when plugins have assets

When the application is configured to serve static assets, the
public/asset paths of the plugins need to be added to the middleware
stack. However, this needs to occur prior to the middleware stack...

Fixes #13050 - Do not pass paths with /assets to helpers

Sprockets 3 does not recommend that, and the new option
`config.assets.raise_runtime_errors` on development.rb will raise errors
on development when doing it.

We only do it in one stylesheet and a helper, so fixing those let...

fixes #13110 - add initializer name to plugin registration deprecation