play/edit controls

the "Play/Edit Controls" are used to control playback and change parameters of the pattern view.

Play: plays from cursor position.
Stop: stops all playback.
Play from the beginning of this pattern: plays from the start of current pattern.
Repeat from the beginning of this pattern: repeats current pattern from its start.
Step one row: plays only the row at cursor position and moves down one.
Edit: toggles edit mode. when turned off, you won't be able to enter notes.
Lock: toggles the order lock, which keeps the cursor in the currently selected order.
Metronome: toggles the metronome, which only works during playback.
Repeat pattern: toggles pattern repeat. during playback while this is on, the current pattern will play over and over instead of following the order list.
polyphony toggle: cycles through the following options.
- Mono: monophony. preview one note at a time only.
- Poly: polyphony. preview multiple notes at once, using other channels of the same type on the same chip. default.
- Chord: chord input. same as polyphony, with the added feature that while keys are held, notes past the first are entered on the same row in adjacent channels.
  - some keyboards have limits on the number of keys that can be held at the same time. this is not a Furnace issue.
Octave: sets current input octave.
Edit Step: sets edit step. if this is 1, entering a note or effect will move to the next row. if this is a larger number, rows will be skipped. if this is 0, the cursor will stay in place.
- if clicked, Step becomes Coarse, which sets the number of rows moved with PgUp, PgDn, and related movement shortcuts. clicking again will revert it to Step.
Follow orders: if on, the selected order in the orders window will follow the song during playback.
Follow pattern: if on, the cursor will follow playback and the song will scroll by as it plays.