Fix realloc across threads.
[example] Implement basic distortion.
[vst client] Debug break instead of crash in case of unrecoverable error.
             Fix wrong late message queue processing in audio thread callback.
             Example plugin now loads in VSTHost and Orion but does not modify input sound.
[vst client] Fix relying on effSetSpeakerArrangement.
             Fix example overwruting zeros.
[vst client] Fix double use of output scratch buffers in processReplacing.
             Signal effFlagsCanDoubleReplacing.