Fix has_migrations? check in Rails::Engine

Refactor sprockets asset paths to allow for alternate asset environments

Provide a more explicit message when we try to redirect to a missing location

This fixes the problem of having a non-explicit message when the :location option is not provided in respond_with.

Make to_json take a parameter to exclude root

This reverts commit 987eb7d4.

This reverts commit 7c562d5e.

Conflicts:

	actionpack/lib/action_view/helpers/form_helper.rb

Fixed ActionView::FormOptionsHelper#select with :multiple => false

Remove AssociationReflection#create_association and AssociationReflection#create_association! - they are not called from anywhere.

Assign the association attributes to the associated record before the before_initialize callback of the record runs. Fixes #1842.

Document the change to Array.wrap's behaviour that was made in b4d8c7d1