Wrap the comment-notify form elements in a DIV and remove needless br

I see that currently you are using a <br id="notify_clear"/> to clear the floats on the options, this would be fixed by the feature request i post here.

The idea would be to wrap the whole form on a <div id="comment-notify"> for example, and then in the CSS:

div#comment-notify .form-radios {
  overflow: hidden;
  heigh: 100%;
}

This would also mean that themers could theme the whole form, adding padding to the whole thing, margins, or give a specific styling to elements within this specific form. We could also use jQuery to open it nicely with a slideDown, or well, you get the idea. The thing is that it would then be targetable both in CSS and in jQuery.

I'm attaching a patch that gets this done, though be aware that this is my very first patch, I created it with Cervisia, so please let me know if the formating or whatever is incorrect.

Also, I'm not sure if this is the best way to wrap it but it does the trick on my test server... let me know what you think :)