Gestrument updates to work alongside ScaleGen and more besides

Here's what's new in Gestrument:

• Allow opening scale files created by our new app ScaleGen
• Support 64-bit devices
• Support new Audiobus 2.1 and Inter-App Audio
• Add new bundled presets
• Fix rate/review link

• KNOWN ISSUE - The Preset menu doesn't change Preset names on the iPhone, even though the selected preset is active. New version submitted to the AppStore