www: Add a html/ directory

This can be used to store HTML templates.

Issue #71.
Add a tempalte interface

This adds a template.php file with the render_template() function which
can be used to load and display a html template. As can be seen, it is
very unsophisticated at this stage.

Issue #71.
Add a template test
build/lib: Silence rsync output
build/www: Add TEMPLATE files to HTML file list

This allows content hashing for the JS and CSS rules.

Issue #71.
template.php: Make $template_args argument optional

Issue #71.
test.php: Start incorporating site contents

Issue #71.
Rename {footer,header}.html to {footer,header}-nav.html

Issue #71.
Move HTML into header and footer

Issue #71.
html/header.html: Use a {{ title }} variable

Issue #71.
html: Abstract layout

Issue #71.
html: Replace search with results content

Issue #71.
Replace results.php with test.php

Issue #71.
html/header-nav.html: Add control flow for header

Issue #71.
html/results.html: Set the header variable appropriately

Issue #71.
header.html: Add page variable which contains page.title

Issue #71.
layout.html: Add an optional page title

Issue #71.
Add an advanced page template

Issue #71.