Changed raw pointer to shared_ptr in DOFVector and DOFMatrix

examples/CMakeLists.txt

examples/surface.cc

src/amdis/DirichletBC.inc.hpp

src/amdis/FileWriter.hpp

src/amdis/PeriodicBC.inc.hpp

src/amdis/ProblemInstat.inc.hpp

src/amdis/ProblemStat.inc.hpp

src/amdis/common/TypeTraits.hpp

src/amdis/gridfunctions/DOFVectorView.hpp

src/amdis/gridfunctions/DiscreteFunction.hpp

src/amdis/gridfunctions/DiscreteFunction.inc.hpp

src/amdis/linearalgebra/DOFMatrixBase.hpp

src/amdis/linearalgebra/DOFVectorBase.hpp

src/amdis/linearalgebra/eigen/DOFVector.hpp

src/amdis/linearalgebra/istl/DOFVector.hpp

src/amdis/linearalgebra/mtl/DOFVector.hpp

test/ExpressionsTest.cpp

test/IntegrateTest.cpp