Feature request: whammy modulation

[ucbmusictreasurer]

On multitracks where we have an isolated guitar channel, can we have the return of the whammy modulation? It would be great to have an option for a number of semitones to modulate through. I believe the default from the official games was either 1 or 2 semitones.

[jbienz]

@TheNathannator and @RileyTheFox, I was wondering if either of you could comment on what went wrong with whammy modulation in the past? I see #487 and #513 as attempts, but it appears they were rolled back.

I believe I may have fully implemented it tonight, though this is my first attempt at modifying the YARG codebase. I did connect it up to FiveFretPlayer and updated existing features that were there but commented out.

My two pull requests for this feature are:

YARG.Core: YARC-Official/YARG.Core#192

YARG Front End: #812

These PR's include details on what was changed / added. Probably the most controversial change is updating WHAMMY_FFT_DEFAULT in GlobalAudioHandler to 512 in an attempt to reduce latency between the guitar track and other tracks when pitch change is enabled. I am aware that there are notes mentioning that changing the FFT size causes BASS to crash, but I was not able to reproduce that. I don't know if the BASS version has been updated in this past year. I can of course remove this change. Another option would be to remove the pitch filter after whammy has been sitting at 0 for a period of time, but I couldn't figure out how to get an update tick in FiveFretPlayer.

I will join the Discord server to make it easier to discuss this PR there.

[RileyTheFox]

This has been merged to our engine-refactor branch. It has been added behind an experimental features settings tab and disabled by default. It will be in the nightly version when we push v0.13 to nightly in about a month