Update attribute to gvp:recordutterance

SUMMARY: Update unknown attribute saveutterance to recordutterance.

The next publication of the GVP 8.1 Voice XML Help will include this revision:

TOPIC: Recognizing Recorded Utterance
SECTION: Usage
Description:
The "GVP 8.1 Voice XML Help" document contains a "Recognizing Recorded Utterance" topic. In the 3rd example (Speech input from the recording of the caller's earlier input), it suggests using "saveutterance" as an attribute of <field>:

<?xml version="1.0"?>
<vxml version="2.1" xmlns="http://www.w3.org/2001/vxml">
  <meta name="maintainer" content="<yourname>@<yourserver.com>"/>
  <meta name="application" content="Recorded Audio Input 3"/>
  <property name="ASRENGINE" value="SPEECHWORKS"/>
  <property name="bargein" value="false"/>
  <form>
     <grammar xml:lang="en-US" version="1.0" root="ROOT"
              xmlns="http://www.w3.org/2001/06/grammar" type="application/srgs+xml">
        <rule id="ROOT" scope="public">
           <item> goodbye <tag>command='goodbye';</tag> </item>
        </rule>
     </grammar>
     <field name="field1" saveutterance="true" slot="command">
        <prompt>
           Please say goodbye.
        </prompt>
        <catch event="nomatch noinput">
           Try again.
           <reprompt/>
        </catch>
        <filled>
           I recognized goodbye with a confidence of 
           <value expr="field1$.confidence"/>.
           Let's make sure I'm a consistent recognizer.
        </filled>
     </field>
     <field name="field2" audioinexpr="field1$.utteranceaudio" slot="command">
        <prompt>
           Please say goodbye.
        </prompt>
        <filled>
           I recognized goodbye with a confidence of
           <value expr="field2$.confidence"/>.
           <if cond="field1$.confidence == field2$.confidence">
              See, I am a consistent recognizer!
           <else/>
              I guess I'm not a consistent recognizer.
           </if>
        </filled>
     </field>
  </form>
</vxml>

This should be updated to "gvp:recordutterance".

The namespace extension should be added to the <vxml> tag. That is, change:

<vxml version="2.1" xmlns="http://www.w3.org/2001/vxml">

To:

<vxml version="2.1" xmlns="http://www.w3.org/2001/vxml" xmlns:gvp="http://www.genesyslab.com/2006/vxml21-extension">

Also, change saveutterance to recordutterance in the following line in the Getting Started section, on the same page:

The shadow variable $.utteranceaudio from an earlier <field>, if saveutterance is enabled.