Add intro to any Chrome app API that has nothing in place already.

chrome/common/extensions/docs/templates/articles/app_hardware.html

Index: chrome/common/extensions/docs/templates/articles/app_hardware.html
diff --git a/chrome/common/extensions/docs/templates/articles/app_hardware.html b/chrome/common/extensions/docs/templates/articles/app_hardware.html
index c9fc8b0136cd89f2a042cf709fcf582ecd372e16..8d044278bc34939b3fc8e6437896b7384aab3145 100644
--- a/chrome/common/extensions/docs/templates/articles/app_hardware.html
+++ b/chrome/common/extensions/docs/templates/articles/app_hardware.html
@@ -5,12 +5,12 @@
 This doc shows you how packaged apps can connect to USB devices
 and read from and write to a user's serial ports.
 See also the reference docs for the
-<a href="experimental.usb.html">USB API</a>
+<a href="usb.html">USB API</a>
 and the
 <a href="serial.html">Serial API</a>.
-The <a href="experimental.bluetooth.html">Bluetooth API</a> has just landed and
-we'll write more on this soon.
-We've included a link to an early sample below.
+The <a href="bluetooth.html">Bluetooth API</a> is also available
+(<a href="app_known_issues.html">known issues</a> still to be resolved);
+we've included a link to a Bluetooth sample below.
 </p>
 
 <p class="note">
@@ -20,7 +20,7 @@ Check out the
 <a href="https://github.com/GoogleChrome/chrome-app-samples/tree/master/serial">serial</a>,
 <a href="https://github.com/GoogleChrome/chrome-app-samples/tree/master/servo">servo</a>,
 <a href="https://github.com/GoogleChrome/chrome-app-samples/tree/master/usb">usb</a>,
-and <a href="https://github.com/GoogleChrome/chrome-app-samples/tree/master/bluetooth-demo">bluetooth-demo</a> samples.
+and <a href="https://github.com/GoogleChrome/chrome-app-samples/tree/master/zephyr_hxm">bluetooth</a> samples.
 </p>
 
 <h2 id="usb">Accessing USB devices</h2>