0.8

• refactoring template formatting for input_spec
• fixing issues with input fields with extension (and using them in templates)
• adding simple validators to input spec (using `attr.validator)
• adding create_dotfile for workflows, that creates graphs as dotfiles (can convert to other formats if dot available)
• adding a simple user guide with input_spec description
• expanding docstrings for State, audit and messanger
• updating syntax to newer python