LOTS of changes to properly handle post/topic revisions

FIX: history revision can now properly be hidden
FIX: PostRevision serializer is now entirely dynamic to properly handle
hidden revisions
FIX: default history modal to "side by side" view on mobile
FIX: properly hiden which revision has been hidden
UX: inline category/user/wiki/post_type changes with the revision
details
FEATURE: new '/posts/:post_id/revisions/latest' endpoint to retrieve
latest revision
UX: do not show the hide/show revision button on mobile (no room for
them)
UX: remove CSS transitions on the buttons in the history modal
FIX: PostRevisor now handles all the changes that might create new
revisions
FIX: PostRevision.ensure_consistency! was wrong due to off by 1
mistake...
refactored topic's callbacks for better readability
extracted 'PostRevisionGuardian'

lib/tasks/posts.rake

@@ -48,7 +48,7 @@ task 'posts:normalize_code' => :environment do
   Post.where("raw like '%<pre>%<code>%'").each do |p|
     normalized = Import::Normalize.normalize_code_blocks(p.raw, lang)
     if normalized != p.raw
-      p.revise(Discourse.system_user, normalized)
+      p.revise(Discourse.system_user, { raw: normalized })
       putc "."
       i += 1
     end