Changelog:

- Sliders did not obey UI scaling. Fixed.

- Uses/used by lines did not obey UI scaling. Fixed.

- New ui widget: plotxy. plotxy(x) plots (x,prevx),  plotxy(x,y) plots (x,y). Both draw 1024 points.

- Sample & hold & interpolate: hold() has a new optional parameter: 0 for old behavior, 1 to interpolate between values, -1 to interpolate in the wrong direction, and other values to get values between old and new value.

- Lock audio thread while changing MIDI devices to avoid crashes

- Midioutprog sent out wrong messages, fixed

- New option: reload last project on startup

- Scope, a separate window with 10 second capture buffer and other doodads. use probe(ch, val) to capture data. Up to 4 channels.

- Virtual midi keyboard, playable with mouse with mod and pitch wheel. Not really usable as an instrument but handy to generate test data

  while midi controller is not available.