updated README; sanitize script parameter in index.php; sanitize description fields of entities (thx to zerody for pointing these out)

Signed-off-by: Michael Kaufmann <d00p@froxlor.org>

lib/Froxlor/Validate/Validate.php

@@ -10,6 +10,8 @@ class Validate
 
 	const REGEX_CONF_TEXT = '/^[^\0]*$/';
 
+	const REGEX_DESC_TEXT = '/^[^\0\r\n<>]*$/';
+
 	/**
 	 * Validates the given string by matching against the pattern, prints an error on failure and exits
 	 *