doc: clean up docs page, refer to wiki, change install doc paths

R=golang-dev, minux.ma, r
CC=golang-dev
https://golang.org/cl/5728051
diff --git a/doc/install.html b/doc/install.html
index 217b52a0..4f2bb1c 100644
--- a/doc/install.html
+++ b/doc/install.html
@@ -1,6 +1,6 @@
 <!--{
 	"Title": "Getting Started",
-	"Path":  "/install/"
+	"Path":  "/doc/install"
 }-->
 
 <h2 id="introduction">Introduction</h2>
@@ -19,9 +19,9 @@
 
 <p>
 For information about installing the <code>gc</code> compiler from source, see
-<a href="/install/source/">Installing Go from source</a>.
+<a href="/doc/install/source">Installing Go from source</a>.
 For information about installing <code>gccgo</code>, see
-<a href="/install/gccgo/">Setting up and using gccgo</a>.
+<a href="/doc/install/gccgo">Setting up and using gccgo</a>.
 </p>
 
 <h2 id="download">Obtaining the Go tools</h2>
@@ -43,8 +43,8 @@
 <p>
 If a binary distribution is not available for your
 OS/arch combination you may want to try
-<a href="/install/source/">installing from source</a> or
-<a href="/install/gccgo/">installing gccgo instead of gc</a>.
+<a href="/doc/install/source">installing from source</a> or
+<a href="/doc/install/gccgo">installing gccgo instead of gc</a>.
 </p>
 
 <h2 id="install">Installing the Go tools</h2>