Custom overwrites not working

[dematerializer]

The "Custom Overwrites" example from the readme isn't working. In getConfig, params/options are being merged into config selectively, allowing not all, but only a handful of favicon_generation settings to be overwritten.

[haydenbleasel]

Hey @dematerializer, thanks for the report. I'm merging this issue into Favicons 4.0. I'd love for you to join in the discussion: #51