fprop and ftrans can't handle match statements

[lecopivo]

fprop and ftrans tactics can't handle match statements

likely #15 has to be solved first

This should work

import SciLean
open SciLean

example : IsDifferentiable ℝ (fun ((x,y,z) : ℝ×ℝ×ℝ) => z) := by fprop

example 
  : (cderiv ℝ (fun ((x,y,z) : ℝ×ℝ×ℝ) => z))
    =
    fun (x,y,z) (dx,dy,dz) => dz := by ftrans only

[lecopivo]

This is broken for unrelated reasons now. Investigate!