0.5.0

What's Changed

• removed Optimizer trait by @lucidfrontier45 in #7
• refactored hill climbing by introducing batch_size by @lucidfrontier45 in #8
• changed OptModel::generate_trial_state to return objective value as well by @lucidfrontier45 in #9
• changed OptModel::generate_trial_state to accept optional current_score arg by @lucidfrontier45 in #10
• improved logic of optimizers by @lucidfrontier45 in #11
• add tsp example by @lucidfrontier45 in #12

Full Changelog: 0.4.1...0.5.0