Implement revamped beatmap converter

[LumpBloom7]

This is a complete rewrite of how std beatmaps are converted, with the end result being more dependent on the original std map, rather than RNG from a fixed set of patterns.

Main changes

• Note positions are now based entirely on the original map

  • The starting note (or any note that is chronologically distance from the previous) will use the angle around the centre of the std playfield to determine the lane
  • Stacks will result in the note being on the same lane
  • Notes in a stream will go clockwise or counter-clockwise based on the original stream direction

• Slides are now more frequent, dropping the previous HitWhistle requirement.

  • Lane is chosen like the above, except any note following closely after a slide will be on the same lane the Slide ends on.
  • Slide bodies are still chosen randomly, but will now take into account the duration of the original std sliders, and use paths more suited to that duration.

• Touch notes have been excluded for now, I currently have no idea on how to include them while making them feel nice