Handle newlines in *_functions.markdown files correctly.

There is code in the ``getclass`` method that handles method and variable descriptions in the markdown files which  contain newlines, preventing the parser from stripping them out.

I've added the same code to the ``getfunctionsfile`` method, so  function documentation newlines are no longer stripped.

This addresses problems that I found in the ``ofRectangle_functions.markdown`` documentation, as well as (at least the newline parts of) issue #56.