Reduce errors and compiletime in tree traversal

cmake/modules/AmdisCXXFeatures.cmake

config.h.cmake

examples/CMakeLists.txt

src/amdis/BoundaryManager.hpp

src/amdis/DataTransfer.inc.hpp

src/amdis/DirichletBC.hpp

src/amdis/PeriodicBC.inc.hpp

src/amdis/ProblemStat.inc.hpp

src/amdis/common/ForEach.hpp

src/amdis/common/TypeTraits.hpp

src/amdis/gridfunctions/DiscreteFunction.inc.hpp

src/amdis/linearalgebra/DOFMatrixBase.inc.hpp

src/amdis/linearalgebra/DOFVectorBase.inc.hpp

src/amdis/typetree/CMakeLists.txt

src/amdis/typetree/Traversal.hpp

src/amdis/typetree/TreeData.hpp

src/amdis/typetree/Visitor.hpp

test/DataTransferTest.hpp

test/TreeDataTest.cpp