gitadora: various fixes for wailing (#513)

## Link to GitHub Issue, if one exists
Fixes #512

## Description of change
Fix digital wailing not being recognized consistently.

Also address the fact that wailing was completely broken when lefty mode
was on. This requires a new option that the user needs to check off in
the configurator since we can't magically guess if the user is holding
the guitar in lefty mode.

- [x] fix downward wail
- [x] digital lefty mode
- [x] implement all of this for arena model i/o
- [x] test dx cab 2p
- [x] lefty toggle in overlay
- [x] fix analog not working for 2p guitar
- [ ] analog lefty mode?

## Testing
Checked GW and GW Delta

src/spice2x/launcher/options.h

@@ -100,6 +100,7 @@ namespace launcher {
             LoadGitaDoraModule,
             GitaDoraTwoChannelAudio,
             GitaDoraCabinetType,
+            GitaDoraLefty,
             LoadJubeatModule,
             LoadReflecBeatModule,
             LoadShogikaiModule,