Error handler should only allow notices etc in smarty templates, not beyond

[rudiedirkx]

If the error handler allow properties are true (default), Smarty catches ALL notices (in short) for ALL code that STARTS in a Smarty template. That's a bit too much. This notice should be caught like now:

{{$nonExistingVar}}

That throws an Undefined array key from 24555ff3ba201974a27652ea2c61a898c2df0cb8_0.file.bla.tpl and we want to catch that. That's good.

But this one should NOT be caught by the Smarty error handler:

{{$existingObject->existingMethod()}}

function existingMethod() {
    return $this->existingArray['nonExistingKey'];
}

That also throws an Undefined array key, but NOT from compiled template code. But Smarty catches and suppresses it anyway. I don't think that's what we want.

Can Smarty_Internal_ErrorHandler::handleError() check for the source of the error? If it's not a smarty compiled template file, let it through.

[rudiedirkx]

See #840