[GH #392] Implement Sobel and Scharr operators

From: Mateusz Loskot (mateusz_at_[hidden])
Date: 2019-10-29 08:03:28

Stefan,

This is one from Olzhas is the only PR that is waiting for (your) review:
https://github.com/boostorg/gil/pull/392

This PR is planned for Boost 1.72, so I'd say it is quite urgent to
review, approve and merge, or postpone.

Best regards,
-- 
Mateusz Loskot, http://mateusz.loskot.net