update README

Author: hhugo

README

@@ -15,15 +15,17 @@ Libraries:
  * findlib
  * react             (tested with 0.9.3)
  * ocamlssl          (tested with 0.4.6)
- * lwt 	             (need version >= 2.4.2, with react and ssl support)
+ * lwt               (need version >= 2.4.2, with react and ssl support)
  * ocamlnet          (tested with 3.6, with netstring, netstring-pcre and netsys)
  * pcre-ocaml        (tested with 6.2.5)
  * cryptokit         (tested with 1.6)
  * ocaml-text        (tested with 0.6)
- * tyxml	     (need version 2.2)
+ * tyxml             (need version 2.2)
+ * ipaddr            (need version >= 2.1)
  * ocamlsqlite3      (tested with 2.0.2) OR
  * dbm               (tested with 1.0)
 
+
 Optional libraries:
 
  * camlzip           (tested with 1.04)