add expire rules mimicking that of the apache config

These rules are closer to the expire logic defined for apache, and also
use a none-capturing regex which will be (unnoticably) faster.

Added a comment as to why there is no default expire header defined.

nginx.conf

@@ -101,24 +101,44 @@ http {
     # Custom 404 page
     error_page 404 /404.html;
 
-    # Static assets
-    location ~* ^.+\.(manifest|appcache)$ {
+    # No default expire rule. This config mirrors that of apache as outlined in the
+    # html5-boilerplate .htaccess file. However, nginx applies rules by location, the apache rules
+    # are defined by type. A concequence of this difference is that if you use no file extension in
+    # the url and serve html, with apache you get an expire time of 0s, with nginx you'd get an
+    # expire header of one month in the future (if the default expire rule is 1 month).
+    # Therefore, do not use a default expire rule with nginx unless your site is completely static
+
+    # cache.appcache, your document html and data
+    location ~* \.(?:manifest|appcache|html|xml|json)$ {
       expires -1;
       access_log logs/static.log;
     }
 
-    # Set expires max on static file types (make sure you are using cache busting filenames or query params):
-    location ~* ^.+\.(css|js|jpg|jpeg|gif|png|ico|gz|svg|svgz|ttf|otf|woff|eot|mp4|ogg|ogv|webm)$ {
-      # This is pretty long expiry and assume your using
-      # cachebusting with query params like
-      #   <script src="application.js?20110529">
-      #
-      # Just be careful if your using this on a frequently
-      # updated static site. You may want to crank this back
-      # to 5m which is 5 minutes.
-      expires 1M; # yes one month
+    # Feed
+    location ~* \.(?:rss|atom)$ {
+      expires 1h;
+      add_header Cache-Control "public";
+    }
 
+    # Favicon
+    location ~* \.ico$ {
+      expires 1w;
       access_log off;
+      add_header Cache-Control "public";
+    }
+
+    # Media: images, video, audio, HTC, WebFonts
+    location ~* \.(?:jpg|jpeg|gif|png|ico|gz|svg|svgz|ttf|otf|woff|eot|mp4|ogg|ogv|webm)$ {
+      expires 1M;
+      access_log off;
+      add_header Cache-Control "public";
+    }
+
+    # CSS and Javascript
+    location ~* \.(?:css|js)$ {
+      expires 1Y;
+      access_log off;
+      add_header Cache-Control "public";
     }
 
     # opt-in to the future