Fixed changing sound of a playing pipe without Pipe999IsTremulant when a wave tremulant state is changed https://github.com/GrandOrgue/grandorgue/issues/1855

[oleg68]

Resolves: #1855

This PR fixes a sound artifact when changing a wave tremulant state. For this it

• adds a member GOSOundSample::m_WaveTremulantStateFor for saving the Pipe999IsTremulant value of current sounding loop
• Renames
  • GOSoundingPipe::m_Sampler to p_CurrentLoopSampler
  • GOSoundEngine::StartTaskSample to CreateTaskSample
  • GOSoundEngine::SwitchAttackSampler to SwitchToAnotherAttack
  • Introduces
  • GOSoundProvider::IsWaveTremulant
  • GOSoundProvider::IsWaveTremulantStateSuitable
  • Removes GOSoundingPipe::m_IsWaveTremulantActive in favor of m_SoundProvider.IsWaveTremulant()
  • Addes checking of Pipe999IsTremulant of the current sounding loop in GOSoundingPipe::SetWaveTremulant

[oleg68]

@larspalo @rousseldenis could you approve this PR?