Brother MFC-J4620DW works over WSD

[hijackeel]

"If you have success with a scanner not included into this list, please let me know."

Reporting that Brother MFC-J4620DW works over WSD. :)

scanimage -L
device airscan:w1:Brother MFC-J4620DW' is a WSD Brother MFC-J4620DW ip=xxx.xxx.xxx.xxx

[alexpevzner]

Thanks for reporting that! README.md updated.