0.0.16-beta

1. Add user mappable cooldown button in extrude panel (default maps extruder=0,heater_bed=0). Use attribute cooldown in guppyconfig.json to remap to another macro.
2. Add limits panel (max velocity, max acceleration, max accel to decel, square corner velocity).
3. Added Pressure Advance in Fine Tune panel.
4. Added button to restart/update Guppy Screen under Settings.