Fixed boolean check methods when using 'config.use_name_as_value = true'.
Merge pull request #27 from Drachenfels-GmbH/name_as_value_bugfixes

Fixed boolean check methods when using 'config.use_name_as_value = true'...
Merge branch 'master' of https://github.com/adzap/active_enum
Not overwriting attribute setter.