TTWavetable: fix for crash with no interpolation and no modulator input
TTWavetable: fix for crash with no interpolation and no modulator input

jamoma/JamomaCore,jamoma/JamomaCore,eriser/JamomaCore,jamoma/JamomaCore,eriser/JamomaCore,jamoma/JamomaCore,eriser/JamomaCore,jamoma/JamomaCore,jamoma/JamomaCore,eriser/JamomaCore,jamoma/JamomaCore,eriser/JamomaCore,eriser/JamomaCore,eriser/JamomaCore,eriser/JamomaCore