Log Message:
frei0r: update to 1.8

1.8   - 27 March 2021

What's Changed:
Consolidated opencv4 support
spelling fixes
using the void keyword in function declaration
Add FX aech0r . Aim to simulate an analog video echo.
Fix build for opencv4
Fill uninitialized gaps between grid images
Avoid destructing alpha channel.
pixeliz0r: Limit the blocksize to a minimum of 1 pixel
edgeglow: Fix hsl to rgb conversion