function MsPowerpoint_SlideIsIt($FileName) {
		$this->MsPowerpoint_InitSlideLst();
		foreach ($this->OpenXmlSlideLst as $i => $s) {
			if ($FileName==$s['file']) return true;
		}
		return false;
	}
function MsPowerpoint_SlideIsIt($FileName) {
		$this->MsPowerpoint_InitSlideLst();
		foreach ($this->OpenXmlSlideLst as $i => $s) {
			if ($FileName==$s['file']) return true;
		}
		return false;
	}
Return true if the file name is a slide.