With the exception of use in three quotes as well as our inlcuded copy
of the GPL, all use of the Free Software Foundation's postal address
has been removed.
Re #320.
- create a probe_lexmar_devices() and call it from sane_init
- call probe_lexmar_devices() from sane_get_devices to update device list
- use sanei_usb_exit() and sanei_usb_find_devices()
- change sanei_lexmark_low_set_scan_regs to have a resolution parameter
- cap sanei_lexmark_low_set_scan_regs resolution to sensor max dpi
when calibrating