Tweaking the curve

[rokujyushi]

Added new curve editing tools to the piano roll.
Added the following new tools to the piano roll toolbar:

• Vertical Stretch Tool
• Horizontal Stretch Tool
• Vertical Shift Tool
• Horizontal Shift Tool

Added tooltips and icons corresponding to these tools, and updated the settings in PianoRoll.axaml, Strings.axaml, and PianoRollStyles.axaml.

Implemented the behavior of the new tools in PianoRoll.axaml.cs and extended the ExpCanvasPointerPressed and ExpCanvasPointerMoved methods.

Added logic to CurveViewModel.cs to support the new tools.
Implemented the TryGetSelection method to retrieve the selection range.

Added new state classes to NoteEditStates.cs and implemented editing logic (move, scale) for each tool.

[nagotown]

Would it be possible to add a setting to ignore any values that are 0/default when using the shift tools?
I also noticed that selection strictly adheres to the snap division grid, is this intentional?

[rokujyushi]

@nagotown
Regarding the setting to ignore values that are 0 or default when using the shift tools, I'm having a hard time imagining how that would behave.

If you don't want to move the default values, I think it's best to simply not select them.

As for the behavior of the selection, I haven't made any specific changes to it, so it remains exactly as it was when the curve selection feature was first added.

[nagotown]

The reason why I wouldn't just select very specific parts is related to the last part of my reply.

It's a bit of a hassle with the grid snapping.
I could just turn off grid snapping, but this means I would have to do it every time I wanted to tweak the pitch.
Drawing pitch doesn't adhere to the grid, so it doesn't make sense to me for it to do that while tweaking the pitch.

By the way, could you check my PR on this branch?
One of the icons is improperly named, causing it to not appear in the expression panel.