Merge branch 'issue/unit_tests' into 'develop'

src/amdis/common/FieldMatVec.hpp

src/amdis/common/TupleUtility.hpp

test/CMakeLists.txt

test/ClonablePtrTest.cpp

test/ConceptsTest.cpp

test/FieldMatVecTest.cpp

test/FilesystemTest.cpp

test/MultiTypeVectorTest.cpp

test/StringTest.cpp

test/TupleUtilityTest.cpp