Add a getting-started link to the pub install docs.

src/site/docs/pub-package-manager/pub-install.markdown

 ---
 layout: default
 title: "pub install"
 description: "Reference documentation for the `pub install` command."
 has-permalinks: true
 ---
 
 # {{ page.title }}
 
+<aside class="note">
+  <a href="index.html" style="text-align: right;">
+    <i class="icon-hand-right icon-white">&nbsp;</i>
+    Looking for the quick start guide? Get started with pub
+  </a>
+</aside>
+
     $ pub install
 
 This command installs all the dependencies listed in the
 [`pubspec.yaml`](pubspec.html) file in the current working directory, as well as
 their [transitive dependencies](glossary.html#transitive-dependencies), to a
 `packages` directory located next to the pubspec. For example:
 
     $ pub install
     Dependencies installed!
 
@@ skipping 42 matching lines @@
 installed. Dependencies downloaded over the internet, such as those from Git and
 [pub.dartlang.org](http://pub.dartlang.org), are stored in a system-wide cache
 and linked to from the `packages` directory. This means that if multiple
 packages use the same version of the same dependency, it will only need to be
 downloaded and stored locally once. It also means that it's safe to delete the
 `packages` directory without worrying about re-downloading packages.
 
 By default, the system package cache is located in the `.pub-cache` subdirectory
 of your home directory. However, it may be configured by setting the `PUB_CACHE`
 environment variable before running Pub.