I have found a problem in Optim.jl using Fminbox and f_calls_limit, it is not well respected the limit.

For instead, using the example for the documentation:

```
julia> using Optim
julia> f(x) = (1.0 - x[1])^2 + 100.0 * (x[2] - x[1]^2)^2;
julia> x0 = [0.0, 0.0];
julia> optimize(f, x0, LBFGS())
* Status: success
* Candidate solution
Final objective value: 5.378405e-17
* Found with
Algorithm: L-BFGS
* Convergence measures
|x - x'| = 4.54e-11 ≰ 0.0e+00
|x - x'|/|x'| = 4.54e-11 ≰ 0.0e+00
|f(x) - f(x')| = 2.85e-19 ≰ 0.0e+00
|f(x) - f(x')|/|f(x')| = 5.29e-03 ≰ 0.0e+00
|g(x)| = 1.21e-13 ≤ 1.0e-08
* Work counters
Seconds run: 0 (vs limit Inf)
Iterations: 24
f(x) calls: 67
∇f(x) calls: 67
```

If a want to restrict the f(x) calls I can use f_calls_limit in Options:

```
julia> optimize(f, x0, LBFGS(), Optim.Options(f_calls_limit=10))
* Status: failure
* Candidate solution
Final objective value: 8.415971e-01
* Found with
Algorithm: L-BFGS
* Convergence measures
|x - x'| = 8.55e-02 ≰ 0.0e+00
|x - x'|/|x'| = 1.00e+00 ≰ 0.0e+00
|f(x) - f(x')| = 1.58e-01 ≰ 0.0e+00
|f(x) - f(x')|/|f(x')| = 1.88e-01 ≰ 0.0e+00
|g(x)| = 1.58e+00 ≰ 1.0e-08
* Work counters
Seconds run: 0 (vs limit Inf)
Iterations: 1
f(x) calls: 10
∇f(x) calls: 10
```

However, if a want to restrict the area this f_calls_limit is less respected:

```
julia> optimize(f, [-5., -5], [5., 5.], x0, Fminbox(LBFGS()), Optim.Options(f_calls_limit=10))
* Status: success
* Candidate solution
Final objective value: 5.377764e-17
* Found with
Algorithm: Fminbox with L-BFGS
* Convergence measures
|x - x'| = 5.23e-07 ≰ 0.0e+00
|x - x'|/|x'| = 3.70e-07 ≰ 0.0e+00
|f(x) - f(x')| = 0.00e+00 ≤ 0.0e+00
|f(x) - f(x')|/|f(x')| = 0.00e+00 ≤ 0.0e+00
|g(x)| = 3.48e-10 ≤ 1.0e-08
* Work counters
Seconds run: 0 (vs limit Inf)
Iterations: 8
f(x) calls: 81
∇f(x) calls: 81
```

However, if I change f_calls_limit the calls is updated, I am not sure if it depends on seed random, but if I does not change f_calls_limit is maintained fixed.

```
julia> optimize(f, [-5., -5], [5., 5.], x0, Fminbox(LBFGS()), Optim.Options(f_calls_limit=40))
* Status: success
* Candidate solution
Final objective value: 5.850631e-17
* Found with
Algorithm: Fminbox with L-BFGS
* Convergence measures
|x - x'| = 6.99e-07 ≰ 0.0e+00
|x - x'|/|x'| = 4.94e-07 ≰ 0.0e+00
|f(x) - f(x')| = 0.00e+00 ≤ 0.0e+00
|f(x) - f(x')|/|f(x')| = 0.00e+00 ≤ 0.0e+00
|g(x)| = 2.64e-10 ≤ 1.0e-08
* Work counters
Seconds run: 0 (vs limit Inf)
Iterations: 3
f(x) calls: 57
∇f(x) calls: 57
```

I am not sure if there is a better way, but I cannot find it.

Thanks in advance.