Adding linked list data structures to the documentaiton.

 On branch master
 Your branch is up-to-date with 'github/master'.

 Changes to be committed:
	new file:   ../docs/ast-utility.dox
	modified:   ../src/verilog_ast_common.h

docs/ast-utility.dox

@@ -0,0 +1,9 @@
+/*!
+@defgroup ast-utility AST Utility Functions
+@ingroup ast
+
+@brief Contains utility data structures and functions which are used to
+help represent portions of the AST, but which are not specific to a
+particular node.
+
+*/

src/verilog_ast_common.h

@@ -13,6 +13,13 @@
 
 // --------------- Linked List ------------------------
 
+/*!
+@defgroup ast-linked-lists Linked List
+@{
+@ingroup ast-utility
+*/
+
+
 //! Typedef for the ast_list_element_t
 typedef struct ast_list_element_t ast_list_element;
 
@@ -60,4 +67,6 @@ void       ast_list_append(ast_list * list, void * data);
 */
 void       ast_list_preappend(ast_list * list, void * data);
 
+/*! @} */
+
 #endif