generate_text_for_display() improper auto-typecast

Function generate_text_for_display() in /includes/functions_content.php is checking too loosely on the parameter $text:

	if (!$text)

	{

		return '';

	}

This won't give back any result if $text has the value "0", since PHP automatically tries to cast strings to integers. That's the reason why "0" == FALSE and !"0" == TRUE and the function thinks the string is empty.

The correct code should be:

	if ($text === '')

	{

		return '';

	}

The bug is trivial, but this function is used in many places.
Reaction to https://www.phpbb.com/community/viewtopic.php?f=71&t=2165721&p=13201648#p13201648