reorg the SDK setup docs to streamline setup for all variations.
Move ADT plugin to the ADT help doc and combine the three setup guides
into one page that is dynamic based on a URL parameter.

Change-Id: If8a8855bdb8e8ec9b0eefedd35ae24ea60497741
diff --git a/docs/html/sdk/index.jd b/docs/html/sdk/index.jd
index 9ee1cca..26e8f30 100644
--- a/docs/html/sdk/index.jd
+++ b/docs/html/sdk/index.jd
@@ -206,12 +206,10 @@
 
 
 <div id="next-steps" style="display:none;position:absolute;width:inherit">
-  <p>Now that you've downloaded the Android SDK, you don't need to return here
-  for SDK updates. The SDK tools allow you to
-  install additional packages and future updates from the SDK Manager.</p>
-  <p>For instructions about setting up your Android SDK for the first time,
-  read <a id="next-link" href="{@docRoot}sdk/installing/bundle.html">Setting
-  Up the ADT Bundle</a>.</p>
+  <p>You're just a few steps away from building apps for Android!</p>
+  <p>In a moment, you'll be redirected to <a
+  id="next-link" href="{@docRoot}sdk/installing/index.html">Installing the
+  Android SDK</a>.</p>
 
 </div><!-- end next-steps -->