name: Add support for ImplicitSha256DigestComponent

This support includes the following new API functions:

- name::Component::isImplicitSha256Digest()
- name::Component::fromImplicitSha256Digest(...)
- Name::appendImplicitSha256Digest(...)
- Updated toUri()/fromUri(...) to support "sha256digest=..." URI
  representation of the ImplicitSha256Digest component

Change-Id: I756c4b94196cf031da98b5689bd60630533dfeb3
Refs: #1640, #2088
diff --git a/src/name.hpp b/src/name.hpp
index 1719e92..9743a96 100644
--- a/src/name.hpp
+++ b/src/name.hpp
@@ -334,6 +334,18 @@
   appendSequenceNumber(uint64_t seqNo);
 
   /**
+   * @brief Append ImplicitSha256Digest
+   */
+  Name&
+  appendImplicitSha256Digest(const ConstBufferPtr& digest);
+
+  /**
+   * @brief Append ImplicitSha256Digest
+   */
+  Name&
+  appendImplicitSha256Digest(const uint8_t* digest, size_t digestSize);
+
+  /**
    * @brief Get the successor of a name
    *
    * The successor of a name is defined as follows: