v0.17.0-pre.4

Generators

• Fix appendStyles and appendScripts signature to match appendFiles.
• option defaults no longer display if default value is an empty string.
• Default options value is now undefined (unless specified otherwise)
• Lots of improvements to the options parsing (kudos to @jridgewell for the awesome work)

Testing helpers

• RunContext#withPrompt and helpers.mockPrompt() can now work without argument - in which case it'll use the default value of each prompt questions.
• A RunContent now automatically mock it's generator prompt.
• Fix multiple bugs with the new RunContext API.
• When a prompt is mocked, it's validation errors are now retrievable on this.prompt.errors. That'll allow you to test your validations methods against incorrect input.