Gestrument goes universal and so much more

A huge update for the already excellent Gestrument. Here's what's new:

• Universal, now also runs on iPhone and iPod touch!
• Allow flipped ranges by swapping min/max for pitches or durations
• Many new presets
• Replaced default soundfont with a stripped down version for better performance
• Add help page about avoiding audio glitches
• JACK support
• Improve lo/mid/hi quality setting. Can now change while connected to Audiobus or JACK and doesn't need a restart of the synth engine
• Keep running in background when 'hold' is toggled
• Show alert if soundfont is missing when loading patch
• Don't allow preset to turn on/off internal synth while we're recording
• Don't re-show tutorial text after visiting editor