Update default configuration

Change the default settings for SSL and modify the tests accordingly.
diff --git a/include/polarssl/config.h b/include/polarssl/config.h
index 4929aa1..8fdf36e 100644
--- a/include/polarssl/config.h
+++ b/include/polarssl/config.h
@@ -1012,7 +1012,7 @@
  *
  * Comment this macro to disable support for SSL 3.0
  */
-#define POLARSSL_SSL_PROTO_SSL3
+//#define POLARSSL_SSL_PROTO_SSL3
 
 /**
  * \def POLARSSL_SSL_PROTO_TLS1