Add const accessor for Problem::Options used by Problem Change-Id: I0fc48178c411887d4487a34599050d342f5344a2
Ceres Solver is an open source C++ library for modeling and solving large, complicated optimization problems. It is a feature rich, mature and performant library which has been used in production at Google since 2010. Ceres Solver can solve two kinds of problems.
Please see ceres-solver.org for more information.