sane-airscan 0.99.27 SANE backend for eSCL (AirScan) and WSD document scanners

This SANE backend lets you scan documents and images from scanners and multi-function printers that speak eSCL (marketed as ``AirScan'') or WSD (or ``WS-Scan'').

Both are vendor-neutral protocols that allow ``driverless'' scanning over IPv4 and IPv6 networks without the vendor-specific drivers that make up most of the sane-backends collection. This is similar to how most contemporary printers speak the universal IPP.

Only scanners that support eSCL will also work over USB. This requires a suitable IPP-over-USB daemon like ipp-usb to be installed and configured.

Any eSCL or WSD-capable scanner should just work. sane-airscan automatically discovers and configures devices, including which protocol to use. It was successfully tested with many devices from Brother, Canon, Dell, Kyocera, Lexmark, Epson, HP, OKI, Panasonic, Pantum, Ricoh, Samsung, and Xerox, with both WSD and eSCL.