Add struct for calculation results

[ohno]

struct Result
    a
    b
    c
end

Base.string(t::Result) = """Result
  a: $(t.a)
  b: $(t.a)
"""

Base.show(io::IO, t::Result) = print(io, Base.string(t))

r = Result(1.0, 2.0, 3.0)
# Result
#   a: 1.0
#   b: 1.0

[ohno]

Update https://github.com/ohno/TwoBody.jl/blob/main/src/FDM.jl too.