The chasing validation release

• Fixed HTML entities being incorrectly included in their escaped form (like " and >) in the search index snippets. (#497)
• Added support for optionally bundling the main CSS files into a single file, to help speed up the first load from a site (controlled by bundle_css and off by default). (#499)
• Added support for optionally inlining the main theming JavaScript code into every generated page, giving the option to reduce the number of JavaScript files that need to be downloaded on the first load of a site (controlled by inline_theme_js and off by default). (#499)
• Changed the site title in the sidebar from an <h1> tag to a <div class="site-title"> to ensure each page has only one primary heading. (#501)
• Added support for responsive sidebar logo image optimisation. When optimise_images is enabled, the sidebar site logo is automatically optimised and rendered as a responsive HTML <picture> element. (#502)