Implement inheritance into ldoc template.

This use the new `@baseclass` and `@inherited` tags to add inheritance data to the rendered documentation.

docs/ldoc.css

@@ -288,6 +288,7 @@ table.module_list td.summary, table.function_list td.summary {
     background-color: white;
     width: 100%;
     border-left-width: 0px;
+    border-right: none;
 }
 
 table.function_list td.shortname {
@@ -334,6 +335,19 @@ table.function_list .function_named_args {
     text-decoration-color: #bbd3ff;
 }
 
+table.function_list td.baseclass {
+    background-color: white;
+    color: #a4c7ff;
+    min-width: 200px;
+    border-left: none;
+    border-right: none;
+    text-align: right;
+}
+
+.baseclass {
+    font-size: 85%;
+}
+
 dl.function {
     margin-right: 15px;
     margin-left: 15px;

docs/ldoc.ltp

@@ -151,6 +151,11 @@
       <td class="name" $(nowrap)><a href="#$(item.name)">$(dn)</a></td>
 #   end
       <td class="summary">$(M(item.summary,item))</td>
+      <td class="baseclass" $(nowrap)>
+#   if item.inherited then
+        Inherited from $(item.baseclass)
+#   end
+      </td>
     </tr>
 #  end -- for items
 # last_kind = kind
@@ -197,6 +202,9 @@
 #   if item.display_type then
     <span class="proptype">($(item.display_type))</span>
 #   end
+#   if item.inherited then
+    <span class="baseclass" $(nowrap)>&nbsp;&middot;&nbsp;Inherited from $(item.baseclass)</span>
+#   end
 #   if ldoc.prettify_files and ldoc.is_file_prettified[item.module.file.filename] then
     <a style="float:right;" href="$(ldoc.source_ref(item))">line $(item.lineno)</a>
 #  end