v0.8.0

Breaking changes

• problem: migrate to Problem<P> design, absorb counting (867f371), closes #32
• problem: typed hard-abort error on problem traits (6b46d57)

Features

• dual-license the package under apache v2 and MIT (9a33eeb)
• solvers: add differential evolution solver (De) (7a09e0a)
• problem: migrate to Problem<P> design, absorb counting (867f371), closes #32
• problem: typed hard-abort error on problem traits (6b46d57)
• problem: fused cost+grad/residual+jac via subtrait hierarchy (c08d595)
• termination: add NoImprovement criterion (c06ff76)
• termination: add TargetCost criteria (690a82b)