Add concept of "skins" to phame, and add a phacility skin

Summary:
introduce an abstract "PhameBlogSkin" class and instantiate two versions -- PhabricatorBlogSkin (Default) and PhacilityBlogSkin.

Most notable hack is including the directory /rsrc/images/phacility - this lets things "work" without messing around with the phacility.com CSS and instead just cutting and pasting most of the file.

Test Plan: played around with Phame a bunch. In particular, created a blog with a custom domain and the phacility skin. Verified it looked good and individual posts looked okay.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T1373

Differential Revision: https://secure.phabricator.com/D3687

src/aphront/configuration/AphrontApplicationConfiguration.php

@@ -153,13 +153,17 @@ abstract class AphrontApplicationConfiguration {
 
       // 2 basic cases
       // -- looking at a list of blog posts, path is nothing or '/'
-      // -- looking at an actual blog post, path is like /btrahan/post_title
+      //    -- we have to fudge the URI in this case
+      // -- looking at an actual blog post, path is like
+      // /phame/posts/<author>/post_title
+      // NOTE: it is possible to get other phame pages, we just do
+      // not link to them at this time.
       if (!$path || $path == '/') {
         $path = $blog->getViewURI();
-      } else {
-        $path = '/phame/posts/'.trim($path, '/').'/';
       }
 
+      PhameBlog::setRequestBlog($blog);
+
       $celerity = CelerityAPI::getStaticResourceResponse();
       $celerity->setUseFullURI(true);
     }