Warn about console output

[thomthom]

Extensions should by default not output debug info in release versions. This is for the sake of keeping that console usage by users and other developers with minimal noise.

Flag puts and p statements. (Maybe $stdout and $stderr as well?) Evaluate if this should go into requirements or suggestions.

There are valid reasons to use this - for development or wrapped in a method that enables/disables the output. In these cases the user can disable per file, line or all together. Main purpose is to spread awareness as this comes up often in extension reviews.