add more customization to jumplines

[bwl21]

Request

I got requests for more customization of jumplines

• [ ] let jumplines join and add the arrow on the join point
• [ ] define jumpline base relative to the note center

Solution approach

• [ ] use the same configuration for Jumplines in general and for the individual jumpline
• [ ] add more parameters:
  • [ ] segments [1,2,3]
  • [ ] jumpline-anchor [x,y]
  • [x] vcut
  • [ ] anchor-base [border | center]
  • [ ] arrow-size [x, y]
  • [ ] shape {1: {cp1:, cp2}, 2:{cp1:, cp2}, 3: {cp1:, cp2}}