v0.4.0

• Added sizes option to the config, specifying the screen size used in the captures [docs]
• Added finished-when option to the config, to indicate when a page has finished loading, defaults to the DOMContentLoaded event [docs]
• Added configtest action, which only validates a config file [docs]
• Added a timeout of 10 seconds to the capture script [source]
• Added functional tests [source]
• Fix: It's now possible to run --help or --version without a (valid) config file