favor of `ActiveRecord::Generators::ActiveModel#update`

There are historical reasons that the `plugin` command was `plugin_new`, now those are no longer applicable, we should remove the naming edge case from the project. This PR is based off of comments from #11176

ATP Railties

Right now if you run the `rails plugin --help` command it fails because rails expects a command in `railties/lib/rails/commands/plugin.rb` that does not exist because the file is named `plugin_new`. This is the error:

```
ruby-2.0.0-p0  ~/documents/projects/tmp/vanilla (master)
$ rails plugin --help
/Users/schneems/.rvm/gems/ruby-2.0.0-p0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in `require': cannot load such file -- rails/commands/plugin (LoadError)
	from /Users/schneems/.rvm/gems/ruby-2.0.0-p0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in `block in require'
	from /Users/schneems/.rvm/gems/ruby-2.0.0-p0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:213:in `load_dependency'
	from /Users/schneems/.rvm/gems/ruby-2.0.0-p0/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in `require'
	from /Users/schneems/.rvm/gems/ruby-2.0.0-p0/gems/railties-4.0.0/lib/rails/commands.rb:49:in `<top (required)>'
	from bin/rails:4:in `require'
	from bin/rails:4:in `<main>'
```

The `rake test:recent` and `rake test:uncommitted` tasks were
deprecated and are now being removed.

Is it more suitable that using ```<th colspan="3">``` instead of three empty ```<th>```? It is simple, but what i am missing about it?

Change repetitive th tags to use colspan attribute

Update CHANGELOG.md

Update CHANGELOG.md

Scaffold generator with --assets=false option 
outputs an error

See #9525

Railtie itself abstract. This stops the weird behavior of forcing
subclasses of Railtie to include the Configurable module.

[ci skip]

[ci skip]

v3 of pull request based on additional feedback from @jeremy

This reverts commit b7d9d6e2.

Per discussion with @jeremy and @rubys on Campfire.

* adds password_digest attribute to the migration
* adds has_secure_password to the model
* adds password and password_confirmation password_fields to _form.html
* omits password entirely from index.html and show.html
* adds password and password_confirmation to the controller
* adds unencrypted password and password_confirmation to the controller test
* adds encrypted password_digest to the fixture

* `rails test -f` will run the test suites with all fixtures loaded
* New application will now generated without `fixtures :all` line
  enabled by default.

To run the whole test suite:

    $ rails test

To run the test file(s):

    $ rails test test/unit/foo_test.rb [test/unit/bar_test.rb ...]

To run the test suite

    $ rails test [models,helpers,units,controllers,mailers,...]

For more information, see `rails test --help`.

This command will eventually replacing `rake test:*`, and `rake test`
command will actually invoking `rails test` instead.

moving changelog note to unreleased section

New beauty pages(404, 422, 500)

Ignore block comments and calculates number of functions.