Release v2.3.0

Bugfixes:

• Use #underscore, not #downcase for help text scope (#140, @atipugin)
• Radio button and checkbox labels will now include the disabled class as needed. (#156, @scottswezey)
• Fixed issue with setting offset in form_group without label in horizontal layout
  when form uses non-default label_col
• Fixed wrapper options (#153, @veilleperso)
• Fix errors on non-ActiveRecord setups (#200, @sgnn7)

Features:

• Allow users to display validation errors in labels (#144, @timcheadle)
• Use humanized attribute name in label errors (#146, @atipugin)
• Allow to skip label rendering (#145, @atipugin)
• Added a required CSS class for labels with required attributes (#150, @krsyoung)
• Added option to customize labels' class.
• Allow callable value_method and text_method for collection_check_boxes and collection_radio_buttons (#199, @shadwell)