Use latest 2.1 version of sprockets-rails
Merge pull request #16649 from Agis-/pg-columns-for-distinct

Fix postgresql adapter #columns_for_distinct trimming whitespace it shouldn't

Conflicts:
	activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb
CHANGELOG & improvements to #16649

* Require either FIRST or LAST qualifier for "NULLS ..."
* Require whitespace before "NULLS ..."

Conflicts:
	activerecord/CHANGELOG.md
Merge pull request #16663 from rubys/4-0-stable

Use latest 2.1 version of sprockets-rails
Correcting #respond_to? method arity

Both of the following methods had method arity of 1:

* Rails::Railtie::Configuration#respond_to?
* ActionDispatch::Response#respond_to?

Other instances of #respond_to? in Rails have a method arity of -2.
The method arity of -2 matches the interface for Ruby 1.9.3, 2.0.0,
2.1.2, and 2.1.0.

See:
http://ruby-doc.org/core-2.1.0/Object.html#method-i-respond_to-3F
http://ruby-doc.org/core-2.1.2/Object.html#method-i-respond_to-3F
http://ruby-doc.org/core-2.0.0/Object.html#method-i-respond_to-3F
http://ruby-doc.org/core-1.9.3/Object.html#method-i-respond_to-3F

Closes rails/rails#16685
Merge pull request #16686 from jeremyf/normalizing-respond-to-method-definitions

Correcting #respond_to? method arity
Merge pull request #16756 from huoxito/dont-mess-railties-default-order

Dont mess with default order engines load (4.1.6.rc1 regression)
Conflicts:
	railties/lib/rails/application.rb