Include all whitespace when removing matched option

Previously, only space was considered. This caused error when the
nspages tag spanned multiple lines and there was no trailing space
before the newline.

Fixes gturri#153

optionParser.php

@@ -162,6 +162,8 @@ static private function preg_match_all_wrapper($pattern, $subject, &$matches){
 
     static private function _removeFromMatch($matched, $match){
         $matched = trim($matched); // to handle the case of the option "-r" which already matches an extra whitespace
-        return substr(str_replace($matched.' ', ' ', $match.' '), 0, -1);
+        // Matched option including any leading and trailing whitespace
+        $regex = '/\s*' . preg_quote($matched, '/') . '\s*/';
+        return preg_replace($regex, ' ', $match);
     }
 }