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'

app/serializers/post_serializer.rb

@@ -233,7 +233,7 @@ class PostSerializer < BasicPostSerializer
   end
 
   def can_view_edit_history
-    scope.can_view_post_revisions?(object)
+    scope.can_view_edit_history?(object)
   end
 
   def user_custom_fields
@@ -258,6 +258,10 @@ class PostSerializer < BasicPostSerializer
     object.via_email?
   end
 
+  def version
+    scope.is_staff? ? object.version : object.public_version
+  end
+
   private
 
     def post_actions