message: small cleanup for  simulated annealing
diff: ///
  /// * [ ] Different acceptance functions
  /// * [ ] Early stopping criterions
  +use rand;
  +use rand::distributions::{IndependentSample, Range};
  use errors::*;
  use problem::Problem;
  use result::ArgminResult;
  use parameter::ArgminParameter;
  -use rand;
  -use rand::distributions::{IndependentSample, Range};
  // use ArgminSolver;
  use ArgminCostValue;
  -use num::Float;
  /// Definition of build in temperature functions for Simulated Annealing.
  ///
  