doc: add more gophers

R=golang-dev, bradfitz, r
CC=golang-dev
https://golang.org/cl/5753047
diff --git a/doc/docs.html b/doc/docs.html
index 52ec28e..f48eb0a 100644
--- a/doc/docs.html
+++ b/doc/docs.html
@@ -31,6 +31,8 @@
 
 <h2 id="learning">Learning Go</h2>
 
+<img class="gopher" src="/doc/gopher/doc.png"/>
+
 <h3 id="go_tour"><a href="http://tour.golang.org/">A Tour of Go</a></h3>
 <p>
 An interactive introduction to Go in three sections.
@@ -117,6 +119,8 @@
 
 <h2 id="talks">Talks</h2>
 
+<img class="gopher" src="/doc/gopher/talks.png"/>
+
 <p>
 The talks marked with a red asterisk (<font color="red">*</font>) were written
 before Go 1 and contain some examples that are no longer correct, but they are
@@ -179,6 +183,8 @@
 
 <h2 id="community">The Go Community</h2>
 
+<img class="gopher" src="/doc/gopher/project.png"/>
+
 <h3 id="mailinglist"><a href="http://groups.google.com/group/golang-nuts">Go Nuts Mailing List</a></h3>
 <p>The <a href="http://groups.google.com/group/golang-nuts">golang-nuts</a> 
 mailing list is for general Go discussion.</p>