Access base_uint through public members (RIPD-898):

* Updates many (but probably not all) locations that access base_uint
  private storage.
* More calls to access base_uint through members.
* Use an iterator to write Serializer collections.

src/ripple/protocol/Serializer.h

@@ -107,6 +107,8 @@ public:
 
     int addVL (Blob const& vector);
     int addVL (Slice const& slice);
+    template<class Iter>
+    int addVL (Iter begin, Iter end, int len);
     int addVL (const void* ptr, int len);
 
     // disassemble functions
@@ -280,6 +282,21 @@ private:
     int addEncoded (int length);
 };
 
+template<class Iter>
+int Serializer::addVL(Iter begin, Iter end, int len)
+{
+    int ret = addEncoded(len);
+    for (; begin != end; ++begin)
+    {
+        addRaw(begin->data(), begin->size());
+#ifndef NDEBUG
+        len -= begin->size();
+#endif
+    }
+    assert(len == 0);
+    return ret;
+}
+
 //------------------------------------------------------------------------------
 
 // DEPRECATED