Add support for a list of functions that should not be used and calls to empty on function results

Sorry for the delayed answer.
Indeed there is no coding style's description, just description of conventions at the end of the page.

So briefly, what you need to know:
- use spaces, not tab
- opening curly braces should be at end of line (not beginning)
- use 2 spaces for indentation
- line should not exceed 120 columns