Implement SV range editor

[IceDynamix]

• Select SV range between start/end offset
  • Toggle for inclusive/exclusive end
  • Status message with count
• Functions
  • Cut/Copy
  • Paste to list of hitobjects
  • Constant length
  • Scale with distance between hitobjects
  • Reverse (for whatever reason?)
  • Add/Multiply offset/velocity
  • Cross add/multiply
  • Delete nth with offset
  • Subdivide by n
  • Subdivide to time
  • Plot

and yes, this is basically re:ambers copier/alter panel