docs: update masthead template for Preview docs

        <div class="wrap" style="position:relative;z-index:1">

        <?cs if:reference ?>

        <?cs # HIDE HELPOUTS RECRUIT BANNER

            <a id="helpoutsLink" class="resource resource-card resource-card-6x2x3 resource-card-6x2 helpouts-card" 

              href="http://helpouts.google.com/partner/landing/provider/googledevelopers?utm_source=dac&utm_medium=banner&utm_campaign=android_provider_banner3" target="_blank">

              <div class="card-bg helpouts-card-bg"></div>

              <div class="card-info">

                <div class="helpouts-description">

                  <div class="text">Help Android Wear and TV developers<br/>

                    <span id="helpoutsLinkText" class="link-color" 

                    style="display:block;padding-top:5px;text-align:right">Learn more</span>

                  </div>

                </div>

              </div>

            </a>

        # END HIDE HELPOUTS ?>

        <?cs /if ?>

            <ul class="nav-x col-9 develop" style="width:100%">

        </a>

      </div>

      <div class="col-8" style="margin:0"><h1 style="margin: 4px 0 0 0px;padding:0;line-height:16px;

color:#666;font-weight:100;font-size:27px;">L Developer Preview</h1></div>

color:#666;font-weight:100;font-size:27px;">M Developer Preview</h1></div>

      <?cs # ADD SEARCH AND MENU ?>

      <?cs call:header_search_widget() ?>

    <div id="butterbar-wrapper">

      <div id="butterbar">

        <a href="http://googleblog.blogspot.com/" id="butterbar-message">

          The Android 5.0 SDK will be available on October 17th!

          The Android {version_number} SDK will be available on {Month} {Day}!

        </a>

      </div>

    </div>