Revert "[1/3] Effects: Add a stereo widening effect"

This reverts commit bb2d6b9b21cf2052b25ff7f9c19a031146846622.
Revert "[2/3] Effects: Add center frequency param to bassboost"

This reverts commit 79362ee0ad93d1dc899b8b7c1f2e801a6eb16d83.