message: better error handling in example
diff: @@ -3,7 +3,7 @@ use argmin::problem::Problem;
  use argmin::sa::{SATempFunc, SimulatedAnnealing};
  use argmin::testfunctions::rosenbrock;
  -fn main() {
  +fn run() -> Result<(), Box<std::error::Error>> {
  // Define cost function
  let cost = |x: &Vec<f64>| -> f64 { rosenbrock(x, 1_f64, 100_f64).unwrap() };
  @@ -15,14 +15,21 @@ fn main() {
  let prob = Problem::new(&cost, &lower_bound, &upper_bound);
  // Set up simulated annealing solver
  - let mut solver = SimulatedAnnealing::new(10.0, 10_000_000).unwrap();
  + let mut solver = SimulatedAnnealing::new(10.0, 10_000_000)?;
  solver.temp_func(SATempFunc::Exponential(0.8));
  // definie inital parameter vector
  // let init_param: Vec<f64> = vec![-1.0, 2.0];
  - let result = solver.run(&prob, &prob.random_param().unwrap()).unwrap();
  + let result = solver.run(&prob, &prob.random_param()?)?;
  // print result
  println!("{:?}", result);
  + Ok(())
  +}
  +
  +fn main() {
  + if let Err(ref e) = run() {
  + println!("error: {}", e);
  + }
  }
  