v0.10.0

Breaking changes

• add best_cost, best_iter and friends to BasicState (c5e425a), closes #36

Features

• solvers: add DeInject solver (ca34b5c)
• add best_cost, best_iter and friends to BasicState (c5e425a), closes #36
• add scratch buffer for simplex state (5255d75)
• add core::observer::Observe<S> trait (6b740ac)
• solvers: add vanilla mini-batch SGD solver (916fa7f)

Performance Improvements

• solvers: reduce allocations in Nelder-Mead (514c4a0)
• speed up SGD::next_iter() (b9fa041)