Less verbose stack traces

Can we do anything about way too long type signature.

```
ERROR: LoadError: LoadError: MethodError: no method matching Bfield(::Interpolations.Extrapolation{Float64, 2, Interpolations.ScaledInterpolation{Float64, 2, Interpolations.BSplineInterpolation{Float64, 2, OffsetArrays.OffsetMatrix{Float64, Matrix{Float64}}, Interpolations.BSpline{Interpolations.Cubic{Interpolations.Line{Interpolations.OnGrid}}}, Tuple{Base.OneTo{Int64}, Base.OneTo{Int64}}}, Interpolations.BSpline{Interpolations.Cubic{Interpolations.Line{Interpolations.OnGrid}}}, Tuple{StepRangeLen{Float64, Base.TwicePrecision{Float64}, Base.TwicePrecision{Float64}}, StepRangeLen{Float64, Base.TwicePrecision{Float64}, Base.TwicePrecision{Float64}}}}, Interpolations.BSpline{Interpolations.Cubic{Interpolations.Line{Interpolations.OnGrid}}}, Interpolations.Flat{Nothing}}, ::Interpolations.Extrapolation{Float64, 1, Interpolations.ScaledInterpolation{Float64, 1, Interpolations.BSplineInterpolation{Float64, 1, OffsetArrays.OffsetVector{Float64, Vector{Float64}}, Interpolations.BSpline{Interpolations.Cubic{Interpolations.Line{Interpolations.OnGrid}}}, Tuple{Base.OneTo{Int64}}}, Interpolations.BSpline{Interpolations.Cubic{Interpolations.Line{Interpolations.OnGrid}}}, Tuple{StepRangeLen{Float64, Base.TwicePrecision{Float64}, Base.TwicePrecision{Float64}}}}, Interpolations.BSpline{Interpolations.Cubic{Interpolations.Line{Interpolations.OnGrid}}}, Interpolations.Flat{Nothing}}, ::Float64, ::Float64, ::COCOS)
```