Use AJAX pagination for the "Check for Spam" button.

[jondavidjohn]

We've run into issues where we have a massive amount of comments. The current "Check for Spam" button's implementation times out because there is no restriction on how many comments to process.

So once a user of this plugin hits an arbitrary number of unapproved comments (depending on server configuration), the "Check for Spam" button breaks and stops working as expected

This patch runs the "Check for Spam" routine via ajax pagination and reloads once complete. This seems like a more bounded and controlled approach.

[jondavidjohn]

Use AJAX to paginate through comments for "Check for Spam" button.

[eoigal]

Check for Spam button now uses ajax pagination