Replaces params in strings
Replacements can be in the following forms:
{PARAM}
Does a replacement with a named parameter, PARAM, specified in any case
{#PLURAL|PARAM|SINGLE|MULTIPLE}
Does a replacement with SINGLE if PARAM (any case) is 1, and with MULTIPLE if PARAM is anything else
{#NL}
Adds a new line to the output
{#URLENC|PARAM}
Returns the specified parameter, urlencode()ed.
{#HTMLENC|PARAM}
Returns the specified parameter, htmlspecialchars()ed.