a bit of Parser.php cleanup

Hi, I thought I submitted this yesterday but I see no record of it ... if you already saw this, ignore it, nothing new since yesterday :)

• Bit of cleanup, removing spaces/tabs at ends of lines and making things a bit more consistent
• Collapsed 4 or 5 simple functions into one `getPart()`
• Fixed minor error in `getAttachments()` ... `$this->getPartContentID()` does not exist, it's `$this->getPartContentId()`