Force FMI functions to be executed in the correct order/ FMU state

[AnHeuermann]

Similar to #64.

The FMI interface functions are only allowed to b executed in a certain order or FMU state. Currently I get errors when I call them in the wrong order. E.g. when calling fmiSimulate before calling fmiInstantiate!:

julia> using FMI
julia> myFMU = fmiLoad("Modelica.Mechanics.MultiBody.Examples.Elementary.Pendulum.fmu")
julia> fmiSimulate(myFMU, 0.0, 1.0; recordValues=["rev.w"])
ERROR: BoundsError: attempt to access 0-element Vector{fmi2Component} at index [0]
Stacktrace:
 [1] getindex(A::Vector{fmi2Component}, i1::Int64)
   @ Base ./array.jl:861
 [2] fmi2Simulate(fmu::FMU2, t_start::Float64, t_stop::Float64; kwargs::Base.Pairs{Symbol, Vector{String}, Tuple{Symbol}, NamedTuple{(:recordValues,), Tuple{Vector{String}}}})
   @ FMI ~/.julia/packages/FMI/K8UGW/src/FMI2.jl:585
 [3] #fmiSimulate#57
   @ ~/.julia/packages/FMI/K8UGW/src/FMI.jl:249 [inlined]
 [4] top-level scope
   @ REPL[5]:1

[ThummeTo]

So in this case, the suggestion would be a better error message?
Best regards!

[AnHeuermann]

Basically yes. For this example I would like an error that tells the user to first call fmiInstantiate!.

For the fmi2XXX functions the error of 3.2.3 State Machine of C Calling Sequence should be checked before calling a function. The FMU itself should issue errors as well, maybe that is already enough.

[ThummeTo]

Issue solved in version 0.3.7

[ThummeTo]

Further, I added checks against the FMI-spec state-machine in 0.3.8.