BButton 2.0 发布，BButton 是 UIButton 的子类，实现类似 Bootstrap 框架中的按钮风格。
值得关注的改动包括：
- Up-to-date for iOS 5.0+, ARC, Storyboards
- Custom initialization methods for easier creation
- Option to show button 'disabled' state
- New button type options
- FontAwesome already included
- Refactored to be much cleaner, better organized