Function interpolate

Computes x,y point at a relative position along compoundpath

interpolate(paths, t, useWidth?, dimensions?): Point
Parameters
- paths: readonly Path[]
  Combined paths (assumes contiguous)
- t: number
  Position (given as a percentage from 0 to 1)
- OptionaluseWidth: boolean
  If true, widths are used for calulcating. If false, lengths are used
- Optionaldimensions: Dimensions
  Precalculated dimensions of paths, will be computed if omitted
Returns Point