[ehmicky]

This PR improves how newlines are handled in transforms:

• The newline is now automatically stripped from each line argument passed to transforms
• yield string statements do not need to add a newline at the end of string anymore. Each yield produces a new line (kindof like console.log()).

The above behavior can be disabled by passing a {transform, newline: true} plain object.

As an added bonus, the stripFinalNewline option now works with the lines option. If lines: true is used, and stripFinalNewline: true is used too, it will be applied to each line, i.e. each item of the result.stdout/result.stderr array.