* fixed issue https://github.com/t0k4rt/phpqrcode/issues/9#issuecomment-45410361
* no needs to echo to get content, qrcode:svg return directly a svg file
* removed header('Content-Disposition: filename="'.$filename.'"'); since it prevents users from changing headers with content type attachment
These changes should not induce bc break
removed force attachment since it can break bc
updated the merged lib
updated svg doctype