Several fixes for Mac

These fixes should be useful for all, even non-Mac.

They relate to either forgotten #includes, forgotten override keywords, or forgotten const keywords. They all caused compilation errors in my MacBook.

include/core/ceres_wrapper/ceres_manager.h

@@ -90,7 +90,7 @@ class CeresManager : public SolverManager
 
         ceres::CostFunctionPtr createCostFunction(const FactorBasePtr& _fac_ptr);
 
-        virtual bool isFactorRegisteredDerived(const FactorBasePtr& fac_ptr) override;
+        virtual bool isFactorRegisteredDerived(const FactorBasePtr& fac_ptr) const override;
 
         virtual bool isStateBlockRegisteredDerived(const StateBlockPtr& state_ptr) override;
 };
@@ -105,7 +105,7 @@ inline ceres::Solver::Options& CeresManager::getSolverOptions()
     return ceres_options_;
 }
 
-inline bool CeresManager::isFactorRegisteredDerived(const FactorBasePtr& fac_ptr)
+inline bool CeresManager::isFactorRegisteredDerived(const FactorBasePtr& fac_ptr) const
 {
     return fac_2_residual_idx_.find(fac_ptr) != fac_2_residual_idx_.end()
             && fac_2_costfunction_.find(fac_ptr) != fac_2_costfunction_.end();