0.4.0

In this release a serie of improvements in the codebase as well as in the generated struct. The new resources can be accessed through:

• UIImage: R.image.[imageName]
• UIStoryboardSegue identifier: R.segue.[segueIdentifier]
• UIStoryboard: R.storyboard.[storyboardName].instance
• Validate images used in the given storyboard: R.storyboard.[storyboardName].validateImages()
• Validate all images in all storyboards: R.validate()