Fixed compiler error in iterator_base friend forward declaration in node on…

Fixed compiler error in iterator_base friend forward declaration in node on clang (and I hope MSVC), plus warnings on clang

include/yaml-cpp/node/detail/impl.h

@@ -23,7 +23,7 @@ namespace YAML
 
 		template<typename Key>
 		struct get_idx<Key, typename boost::enable_if<boost::is_unsigned<Key> >::type> {
-			static node *get(const std::vector<node *>& sequence, const Key& key, shared_memory_holder pMemory) {
+			static node *get(const std::vector<node *>& sequence, const Key& key, shared_memory_holder /* pMemory */) {
 				return key < sequence.size() ? sequence[key] : 0;
 			}
 

include/yaml-cpp/node/detail/iterator_fwd.h

@@ -16,7 +16,7 @@ namespace YAML
 	class node;
 	
 	namespace detail {
-		class iterator_value;
+		struct iterator_value;
 		template<typename V> class iterator_base;
 	}
 

include/yaml-cpp/node/node.h

@@ -21,7 +21,7 @@ namespace YAML
 		friend class NodeBuilder;
 		friend class NodeEvents;
 		friend class detail::node_data;
-		template<typename, typename, typename> friend class detail::iterator_base;
+		template<typename> friend class detail::iterator_base;
 		
 		Node();
 		explicit Node(NodeType::value type);

src/node/nodebuilder.cpp

@@ -31,21 +31,21 @@ namespace YAML
 	{
 	}
 	
-	void NodeBuilder::OnNull(const Mark& mark, anchor_t anchor)
+	void NodeBuilder::OnNull(const Mark& /* mark */, anchor_t anchor)
 	{
 		detail::node& node = Push(anchor);
 		node.set_null();
 		Pop();
 	}
 	
-	void NodeBuilder::OnAlias(const Mark& /*mark*/, anchor_t anchor)
+	void NodeBuilder::OnAlias(const Mark& /* mark */, anchor_t anchor)
 	{
 		detail::node& node = *m_anchors[anchor];
 		Push(node);
 		Pop();
 	}
 	
-	void NodeBuilder::OnScalar(const Mark& mark, const std::string& tag, anchor_t anchor, const std::string& value)
+	void NodeBuilder::OnScalar(const Mark& /* mark */, const std::string& tag, anchor_t anchor, const std::string& value)
 	{
 		detail::node& node = Push(anchor);
 		node.set_scalar(value);
@@ -53,7 +53,7 @@ namespace YAML
 		Pop();
 	}
 	
-	void NodeBuilder::OnSequenceStart(const Mark& mark, const std::string& tag, anchor_t anchor)
+	void NodeBuilder::OnSequenceStart(const Mark& /* mark */, const std::string& tag, anchor_t anchor)
 	{
 		detail::node& node = Push(anchor);
 		node.set_tag(tag);
@@ -65,7 +65,7 @@ namespace YAML
 		Pop();
 	}
 	
-	void NodeBuilder::OnMapStart(const Mark& mark, const std::string& tag, anchor_t anchor)
+	void NodeBuilder::OnMapStart(const Mark& /* mark */, const std::string& tag, anchor_t anchor)
 	{
 		detail::node& node = Push(anchor);
 		node.set_type(NodeType::Map);