Add custom easing, new operators, and position overhaul

• Add simple view, for people using the plugin for the first time, or people who just want to apply a basic linear tween with no other bells or whistles. This captures the simplicity of the very first version of this plugin, and is organized as such.
• Add new easing: custom. Define your own tweener not covered by the plugin's existing options!
• Add tons of new options for mulch positions.
  • Ability to copy paste all notes.
  • Ability to copy paste timestamped notes instead of just position.
  • Ability to filter notes by position.
  • Ability to sort notes by time or position, in ascending or descending order.
  • Ability to specify initial SV.
• Add new operations, previously only add and multiply:
  • subtract
  • divide
  • replace
  • modulo
  • min
  • max
• Expanded maximum number of calculators to 20. No one needs this, but I increased it because it's a nicer number.
• Improved performance significantly, especially relating to the plot rendering. The FPS will no longer halve when you increase resolution of the plot.