- change 300 dpi mode to be in 'half ccd' mode
- fix sensor pixel number
- allow for negative offset in shading data building
- rewrite compute_coefficients to handle negative offset and specialised
it for pixel deletion case
- fix calibration handling of flatbed scanners
- added search_strip function to command set
- coded search_strip for gl646
- initial calibration process for sheetfed scanners upto strip finding
- create a scanner calibration function that switches between
flatbed or sheetfed calibration
- added a sheetfed calibration function
- removed gamma table setting from calibration process
- call gamma setting during sane_start but before scanner calibration