Add Pitch Shifting as an node/effect.

[CoderQCFromScraatch]

Describe the idea you'd like for Amethyst to have
I would like Amethyst to be able to shift the pitch of songs currently played.

Is your feature request related to a problem? Please describe.
Today, I woke up realizing that I hear stuff -0.28 semitones below the pitch they're supposed to be at, and it's completely ruined my ability to listen to music. It's not a device issue, as the problem spans across multiple devices.