Fix for https://github.com/polpo/picogus/issues/46
Attack step is 0 for eg_rate_h 15 causing envelop never switch to decay, causing some music missing notes in higher notes. For fix, step value 0 is treated as special case resetting eg_out to 0 which immediately switches envelop generator to decay.
Fix for https://github.com/polpo/picogus/issues/46 Attack step is 0 for eg_rate_h 15 causing envelop never switch to decay, causing some music missing notes in higher notes. For fix, step value 0 is treated as special case resetting eg_out to 0 which immediately switches envelop generator to decay.