fix CollectionProxy delete_all documentation

This method no longer returns an array of all records that
have been removed. Correct documentation to reflect this change.

See issue 14546
Add documentation for Thread#freeze
Merge pull request #14626 from eileencodes/fix_incorrect_collection_proxy_delete_all_documentation

fix CollectionProxy delete_all documentation
Remove unused `subclass_controller_with_flash_type_bar` var from flash test.
Merge pull request #14624 from jamox/dev_install_guide

Added OS X specific commands to installation guide [ci skip]
Merge pull request #14628 from vipulnsward/remove-flash-test-warning

Remove unused `subclass_controller_with_flash_type_bar` var from flash test.
make enums distinct per class
Merge pull request #14609 from evanwhalen/enums_inheritance

Make enums distinct per class
Ignore order when doing count.

This is necessary because Postgresql doesn't play nice with ORDER BY and
no GROUP BY.

Fixes #14621.
Merge pull request #14631 from laurocaetano/fix_count_with_order

Ignore order when doing count.
Use connection-specific bytea escaping

In our normal usage, it's rare for this to make a difference... but is
more technically correct.

As well as a spec that proves this is a good idea, let's also add a more
sane-looking one that just covers basic to_sql functionality. There
aren't many places where we actually use escape_bytea, but that's one
that won't be going away.
Merge pull request #14632 from matthewd/escape_bytea

Use connection-specific bytea escaping
Build the reverse_order on its proper method.

The reverse_order method was using a flag to control if the order should
be reversed or not. Instead of using this variable just build the reverse order
inside its proper method.

This implementation was leading to an unexpected behavior when using
reverse_order and then applying reorder(nil).

Example:
  Before
    Post.order(:name).reverse_order.reorder(nil)
    # => SELECT "posts".* FROM "posts"   ORDER BY "posts"."id" DESC

  After
    Post.order(:name).reverse_order.reorder(nil)
   # => SELECT "posts".* FROM "posts"
Remove useless begin..end
remove check for present? from delete_all

Passing in a blank string is a bug so there's no reason
to check for a blank string.
Rails.application should be set inside before_configuration hook

Fixes #14620
Merge pull request #14635 from eileencodes/remove-check-for-present

remove check for present? from delete_all method
Merge pull request #14634 from laurocaetano/fix_reorder

Build the reverse_order on its proper method.
Merge branch 'master' into adequaterecord

* master: (122 commits)
  Rails.application should be set inside before_configuration hook
  remove check for present? from delete_all
  Remove useless begin..end
  Build the reverse_order on its proper method.
  Use connection-specific bytea escaping
  Ignore order when doing count.
  make enums distinct per class
  Remove unused `subclass_controller_with_flash_type_bar` var from flash test.
  fix CollectionProxy delete_all documentation
  Added OS X specific commands to installation guide [ci skip] Recommended using homebrew for installing MySQL and PostgreSQL
  Fix setup of adding _flash_types test.
  Use SVG version of travis build status badge [skip ci]
  W3C CSP document moved to gihub.io URL [ci skip]
  sprockets-rails was released
  Fix the test defining the models in the right place
  Add CHANGELOG entry for #11650 [ci skip]
  Declare the assets dependency
  Use sass-rails 4.0.3
  Make possible to use sprockets-rails 2.1
  add missing parentheses to validates_with documentation [skip ci]
  ...
where_values should extract the value of the Casted node

makes adequaterecord work with arel master.