Grain Science gets a little update

Only a small update, but always good to see apps get updates however small. Here's what's new:

• New: Additional sustain modes (select your preference in the Settings from a choice of regular, toggle and auto-reset)
• Fix: Issue where unintended 'popping' noises could occur under certain circumstances
• Issue where it was accidentally possible to incorrectly map ADSR Gain to Velocity in the control mapper
• Fix: Workaround for yet another Dropbox sharing API change