Use space instead of command for tag-input

this makes sure that email aliases wrap. if we used comma, it does not wrap

src/views/email.html

@@ -318,6 +318,7 @@
                       {{ mailbox.ownerDisplayName }}
                     </td>
                     <td class="hand" ng-click="mailboxes.edit.show(mailbox)">
+                      <!-- aliases is spaces separated, so it will wrap as needed -->
                       {{ mailbox.aliases }}
                     </td>
                     <td class="hand" ng-click="mailboxes.edit.show(mailbox)">