Modified docsite layout to use Google custom search.

See changes to docsite/_themes/srtd/layout.html and search.html.  Using custom search form to call Google Custom Search and show results in main content area.  Added custom javascript to show/hide results. Added FontAwesome (loading from cdnjs.com) to get search start/reset icons.  Changed content max width from 800px to 1024px- because we've past the '90s.