Pianoroll enhancements

[felixroos]

I added the following options to .pianoroll:

{
cycles = 4, // number of cycles to show
playhead = 0.5, // position of playhead, 0.5 = center
vertical = 0, // if 1, time will be on the y axis
autorange = 0, // if 1, the range of values will be deduced from the active cycles (instead of minMidi / maxMidi)
fold = 0, // if 1,  there will be no gaps between values (like ableton fold), autorange will be ignored
overscan = 1, // how many extra cycles will be queried outside the viewport, can be used to get a more stable autorange without needing to set cycles higher
flipTime = 0, // if 1, time will flow in the opposite direction
flipValues = 0, // if 1, value range will be flipped
hideNegative = 0, // if 1, haps with negative events will be hidden at start
timeframe, // now deprecated (but still works)
}

[felixroos]

fixes #115