doc: subdivide TOC, add auxiliary links

PR-URL: #6167
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Robert Jefe Lindstädt <robert.lindstaedt@gmail.com>

doc/api/_toc.markdown

@@ -2,6 +2,9 @@
 @// point at the new location.
 * [About these Docs](documentation.html)
 * [Usage & Example](synopsis.html)
+
+<div class="line"></div>
+
 * [Assertion Testing](assert.html)
 * [Buffer](buffer.html)
 * [C/C++ Addons](addons.html)
@@ -39,3 +42,8 @@
 * [V8](v8.html)
 * [VM](vm.html)
 * [ZLIB](zlib.html)
+
+<div class="line"></div>
+
+* [GitHub Repo & Issue Tracker](https://github.com/nodejs/node)
+* [Mailing List](http://groups.google.com/group/nodejs)

doc/api_assets/style.css

@@ -58,6 +58,12 @@ em code {
   font-size: .8em;
 }
 
+.line {
+  width: calc(100% - 1em);
+  display: block;
+  padding-bottom: 1px;
+}
+
 .api_stability {
   color: white !important;
   margin: 0 0 1em 0;
@@ -173,6 +179,12 @@ header h1 {
   padding-top: 1em;
 }
 
+#apicontent .line {
+  width: calc(50% - 1em);
+  margin: 1em 1em .95em;
+  background-color: #ccc;
+}
+
 #toc + h1 {
   margin-top: 1em;
   padding-top: 0;
@@ -351,17 +363,34 @@ a code {
 
 #column2 ul {
   list-style: none;
-  margin: 1.25em 0;
+  margin: .9em 0 .5em;
   background: #333;
 }
 
+#column2 > :first-child {
+  margin: 1.25em 1em;
+}
+
+#column2 > ul:nth-child(2) {
+  margin: 1.25em 0 .5em;
+}
+
+#column2 > ul:last-child {
+  margin: .9em 0 1.25em;
+}
+
 #column2 ul li {
   padding-left: 1.4em;
   margin-bottom: .5em;
   padding-bottom: .5em;
   font-size: .8em;
 }
 
+#column2 .line {
+  margin: 0 .5em;
+  background-color: #707070;
+}
+
 #column2 ul li:last-child {
   margin-bottom: 0;
 }