Remove full url from links where possible

This allows more thorough checks with HTMLProofer.

Rakefile

@@ -20,9 +20,20 @@ end
 desc 'Generate and test a production build of the Jekyll site'
 task build: :clean do
   ENV['JEKYLL_ENV'] ||= 'production'
-  sh(*%W(bundle exec jekyll build
-         --config _config.yml,_config.#{ENV['JEKYLL_ENV']}.yml))
-  HTMLProofer.check_directory('dist', disable_external: true).run
+  configs = %W(_config.yml _config.#{ENV['JEKYLL_ENV']}.yml)
+  config = configs.map(&YAML.method(:load_file)).reduce(&:merge)
+
+  sh(*%(bundle exec jekyll build --config #{configs.join(',')}))
+
+  HTMLProofer.check_directory(
+    'dist',
+    enforce_https: true,
+    check_html: true,
+    check_favicon: true,
+    assume_extension: true,
+    url_ignore: [%r{^#{config['url']}/} => '/'],
+    url_swap: { %r{^#{config['baseurl']}/} => '/' }
+  ).run
 end
 
 desc 'Start a local Jekyll development server'

_config.production.yml

@@ -1,5 +1,2 @@
 baseurl: /jekyll-site
 url: https://makenew.github.io
-
-assets:
-  cdn: https://makenew.github.io

src/_includes/head.html

@@ -5,5 +5,5 @@
 <meta name="msapplication-config" content="none">
 <meta name="mobile-web-app-capable" content="yes">
 <link type="text/plain" rel="author"
-      href="{{ site.url }}{{ site.baseurl }}/humans.txt">
+      href="{{ site.baseurl }}/humans.txt">
 {% include favicon.html %}