Add links to developer portal at api.openstack.org

With the recent addition of a developer portal at api.openstack.org,
let's link to the page.

Change-Id: I86b087445f683b8190069c381f4732aad44305b8

www/grizzly/index.html

@@ -229,6 +229,11 @@
 				
 				<h4 class="special">Develop applications for OpenStack clouds</h4>
 				<dl>
+					<dd><a
+						href="http://api.openstack.org/"
+						>Open source software for application development
+					    on private and public OpenStack clouds</a>
+					</dd>
 					<dd><a
 						href="http://docs.openstack.org/api/quick-start/content/"
 						>API Quick Start</a></dd>

www/havana/index.html

@@ -256,6 +256,11 @@
 
 				<h4 class="special">Develop applications for OpenStack clouds</h4>
 				<dl>
+					<dd><a
+						href="http://api.openstack.org/"
+						>Open source software for application development
+					    on private and public OpenStack clouds</a>
+					</dd>
 					<dd><a
 						href="http://api.openstack.org/api-ref.html"
 						>API Complete Reference</a>

www/index.html

@@ -252,6 +252,11 @@
 
 				<h4 class="special">Develop applications for OpenStack clouds</h4>
 				<dl>
+					<dd><a
+						href="http://api.openstack.org/"
+						>Open source software for application development
+					    on private and public OpenStack clouds</a>
+					</dd>
 					<dd><a
 						href="http://api.openstack.org/api-ref.html"
 						>API Complete Reference</a>

www/trunk/index.html

@@ -254,6 +254,11 @@
 				
 				<h4 class="special">Develop applications for OpenStack clouds</h4>
 				<dl>
+					<dd><a
+						href="http://api.openstack.org/"
+						>Open source software for application development
+					    on private and public OpenStack clouds</a>
+					</dd>
 					<dd><a
 						href="http://api.openstack.org/api-ref.html"
 						>API Complete Reference</a>