[FEATURE] Pre & Post EQ toggle/switch

[38github]

To allow more shaping of tones.

[sdatkinson]

I've seen this before...#49 🙂

I'm willing to do this once #459 is addressed. Otherwise, adding this will cause the plugin to load incorrectly for everyone who's using the plugin in projects now.

[silvansky]

Since #459 is done, I've implemented pre/post for EQ in my fork. Also migration from prev versions is implemented. UI decision: segmented control [Pre|Off|Post]. I think that's better than two switches for on/off and pre/post, I tried both, segmented feels better.

[38github]

Wow, thank you!

[silvansky]

I opened PR to this repo: #637