management: Making LocalControlHeader encoding independent of Interest/Data wire

Boost.Asio support multi-buffer send operation, which is enabled in this
commit for prepending (potentially different) LocalControlHeader's to
Interest/Data wire.

Change-Id: I39b979f89f196d3e47d6466fb71f6d440bce74d4
refs: #1265
diff --git a/src/encoding/block.hpp b/src/encoding/block.hpp
index 895df49..52ed7e7 100644
--- a/src/encoding/block.hpp
+++ b/src/encoding/block.hpp
@@ -56,7 +56,8 @@
    * This version will automatically detect type and position of the value within the block
    */
   Block(const ConstBufferPtr &buffer,
-        const Buffer::const_iterator &begin, const Buffer::const_iterator &end);
+        const Buffer::const_iterator &begin, const Buffer::const_iterator &end,
+        bool verifyLength = true);
   
   /**
    * @brief A helper version of a constructor to create Block from the raw buffer (type and value-length parsing)