#169 TCallback is messing up umlauts

[willydee]

A TCallback containing UTF8 encoded text is messing up
characters like German umlauts when updating it's content.

Test.tpl:
<com:TForm>
<com:TCallback ID="myCallback">dänisch</com:TCallback>
<com:TActiveButton OnCommand="Page.onClickButton"
Text="Do Callback" />
</com:TForm>

Test.php:
class Test extends TCallbackPage
{
public function onClickButton($s,$p)
{
$this->myCallback->flush();
}
}

Result:
dänisch

Result after callback:
dänisch