Fixes failures in Rails 4.2 with I18n changes
Removes support for Rails 3.0 and 3.1
Silences Active Record schema output
Fixes issues and warnings with i18n tests

Since Rails 3.2.16 the enforce_available_locales setting should be set
to true. This mimics that behavior.
Active Record models must explicitly include ClassyEnum

From my experience, it's rare to have more than a few models use
ClassyEnum in a project. By requiring all models to explicitly include
(or extend) ClassyEnum::ActiveRecord, it keeps other models clean and
makes it more obvious where classy_enum_attr is coming from.
Removes support for Ruby 1.8.7

Mostly just converting hashes and lambdas to post 1.9 syntax
Changes classy_enum_attr preferred argument to class_name

The class_name argument was added to bring the API closer to how you
declare class name's with other Rails functionality. To try and prevent
confusion, the other 'enum' argument which did the same thing, has been
removed from the documentation, but is still valid.
Run specs on 4.2 beta until release comes out
Removes null object from ClassEnum::Base.build

The null object was originally added to retain backwards compatibility
with existing Formtastic support. It was a pain to maintain support for
Formtastic, so support was removed, but the null object remained. The
null object breaks expected behavior if you're expecting the value to be
nil since it does not evaluate to a falsy value.

Previously, blank values had the same methods as enums:

  alarm = Alarm.new(priority: nil)
  alarm.priority.nil? # => true
  alarm.priority.low? # => false

Now, the value will be nil:

  alarm = Alarm.new(priority: nil)
  alarm.priority.nil? # => true
  alarm.priority.low? # NoMethodError: undefined method `low?' for nil:NilClass
  alarm.priority && alarm.priority.low? # => nil
Simplifies example for comparing enum values in select
No longer needs to check for anonymous classes

This was left over from the null object functionality that was
previously removed.
Removes serialize_as_json option from classy_enum_attr

This was originally added as a way to expose a JSON version of the enum
instance, but it doesn't really give you anything. If you want to
serialize the enum instances, you can simply override as_json in the
enum classes.
Removes support for Ruby < 2.0

Experimenting with keyword args and they don't work in 1.9.3. Not sure
if it's worth removing support for < 2.0, but that seems like a pretty
old version at this point.
Removes allow_blank option from ClassyEnum::Base.build

This was also used originally to support Formtastic and is no longer
needed.
Updates README to reflect latest API
Allow comparison with enum classes

This addresses the issue of using enums in a case statement and also
makes the API more predictable.
Revert "Removes support for Ruby < 2.0"

This reverts commit 9db4172090adc39c8c8d213f75a7ecfe2049ff01.

Conflicts:
	lib/classy_enum/base.rb

After thinking about this for a bit and looking at some of the recent
surveys on Ruby usage, it seems like a lot of people are still using
1.9.3. Since there's not a huge benefit to dropping support for 1.9.3,
it will stay for now.
Updates spec to ensure the enum option is covered

I thought about removing this in favor of class_name, but it's been
around for so long that it will cause some upgrade headaches for people
without much benefit.
Merge branch 'version-4.0'