example inputs.ipynb doesn't run with v0.13.0

[juguma]

examples/src/inputs.ipynb
doesn't run with v0.13.0, since input function extForce_t(t) doesn't match the proposed input function structure (at least that's what the error says)...

ERROR: AssertionError: The given input function does not fit the needed input function pattern for FMUs, which are: 
- `inputFunction!(t::fmi2Real, u::AbstractArray{fmi2Real})`
- `inputFunction!(comp::FMU2Component, t::fmi2Real, u::AbstractArray{fmi2Real})`
- `inputFunction!(comp::FMU2Component, x::Union{AbstractArray{fmi2Real,1}, Nothing}, u::AbstractArray{fmi2Real})`
- `inputFunction!(x::Union{AbstractArray{fmi2Real,1}, Nothing}, t::fmi2Real, u::AbstractArray{fmi2Real})`
- `inputFunction!(comp::FMU2Component, x::Union{AbstractArray{fmi2Real,1}, Nothing}, t::fmi2Real, u::AbstractArray{fmi2Real})`

[ThummeTo]

Correct, we are currently on restructering the documentation, some of the other examples might fail as well.