Remove the "PHP" style formatting function

The "PHP" formatting function doesn't add anything, except an undocumented date format.

All usages in the templates have been replaced with DateFmtShort and DateFmtLong for convenience.

templates/admin/org/list.tmpl

@@ -35,7 +35,7 @@
 					                            <td>{{.NumTeams}}</td>
 					                            <td>{{.NumMembers}}</td>
 					                            <td>{{.NumRepos}}</td>
-					                            <td><span title="{{DateFormat .Created "r"}}">{{DateFormat .Created "M d, Y"}}</span></td>
+					                            <td><span title="{{DateFmtLong .Created}}">{{DateFmtShort .Created}}</span></td>
 					                        </tr>
 					                        {{end}}
 					                    </tbody>