Tweaking Widget Panel in Conpherence

Summary:
Fixes T3252. Other enhancements:

- Header in widget panel was 2px too short.
- Typeahead in add people only allowed one person
- Typeahead in add people was cutoff by overflow:hidden
- X in remove has been changed to unicode (multiply)
- Add people dialog form fields are full width
- Some other CSS tweaks.

Test Plan: Add, Remove people.

Reviewers: epriestley, btrahan

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T3252

Differential Revision: https://secure.phabricator.com/D6076

src/view/AphrontDialogView.php

@@ -180,9 +180,12 @@ final class AphrontDialogView extends AphrontView {
 
     $content = hsprintf(
       '%s%s%s',
-      phutil_tag('div', array('class' => 'aphront-dialog-head'), $header),
-      phutil_tag('div', array('class' => 'aphront-dialog-body'), $children),
-      phutil_tag('div', array('class' => 'aphront-dialog-tail'), $buttons));
+      phutil_tag('div',
+        array('class' => 'aphront-dialog-head'), $header),
+      phutil_tag('div',
+        array('class' => 'aphront-dialog-body grouped'), $children),
+      phutil_tag('div',
+        array('class' => 'aphront-dialog-tail'), $buttons));
 
     if ($this->renderAsForm) {
       return phabricator_form(