Remove deprecated Rails options from dummy application
Infer spec type from file location

Specs should be compatible with multiple version of Rails.
Rails <= 4 infers the example group from the file location.
Convert deprecated its statements to expectations
Change truthy / falsey specs to real true / false checks
Remove protected_attributes gem from rails4 gemfile
Remove attr_accessible from dummy app models

In spec context using mass assignment
protection is totally unecessary anyway.
Add test task for Rails 4.1
Add eager_load config in all dummy app environments
Merge pull request #201 from fotos/spec_cleanup

Spec cleanup
Add #allow_nil for monetize test helper

Allows testing monetized values that allow and return nil by default.
Update README with allow_nil test helper