Solver manager

Because of #142 (closed) I can't write a proper markdown-based description thus I upload a screenshort ...

• remove former StateBlock notification list
• StateBlock::getState returns by copy
• remove StateBlock::getPtr

src/ceres_wrapper/ceres_manager.cpp

@@ -41,9 +41,6 @@ CeresManager::~CeresManager()
 
 std::string CeresManager::solveImpl(const ReportVerbosity report_level)
 {
-  // update problem
-  update();
-
   // run Ceres Solver
   ceres::Solve(ceres_options_, ceres_problem_.get(), &summary_);