Support sane option --scan-area
Several sane backends provide the option --scan-area to guarantee the scan is correctly aligned, even if the scan area with automatic document feeder (ADF) is right-aligned in contrast to the flatbed of the same device, which is normally left-aligned.
Currently on Ubuntu Simple Scan and XSane only support options -l -t -x -y, which leads to misalignment of some scanners when using the ADF.
As example for this problem see: utsushi/utsushi#68 (closed)