Add _init() and _free() for hash modules
diff --git a/include/polarssl/md5.h b/include/polarssl/md5.h
index bb0ebf3..2f378f6 100644
--- a/include/polarssl/md5.h
+++ b/include/polarssl/md5.h
@@ -67,6 +67,20 @@
 md5_context;
 
 /**
+ * \brief          Initialize MD5 context
+ *
+ * \param ctx      MD5 context to be initialized
+ */
+void md5_init( md5_context *ctx );
+
+/**
+ * \brief          Clear MD5 context
+ *
+ * \param ctx      MD5 context to be cleared
+ */
+void md5_free( md5_context *ctx );
+
+/**
  * \brief          MD5 context setup
  *
  * \param ctx      context to be initialized