Move slowvote loading logic into Query class

Summary: Mostly straightforward. Also fixed a couple of error/darkconsole things.

Test Plan:
  - Created poll;
  - viewed poll;
  - voted in poll;
  - used `V6` and `{V6}` markup styles in poll.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D6458

src/aphront/configuration/AphrontDefaultApplicationConfiguration.php

@@ -121,6 +121,10 @@ class AphrontDefaultApplicationConfiguration
 
     // For non-workflow requests, return a Ajax response.
     if ($request->isAjax() && !$request->isJavelinWorkflow()) {
+      // Log these; they don't get shown on the client and can be difficult
+      // to debug.
+      phlog($ex);
+
       $response = new AphrontAjaxResponse();
       $response->setError(
         array(