Merge branch 'issue/rename_parallel_global_basis' into 'master'

amdis/DOFVector.hpp

amdis/ProblemStat.hpp

amdis/ProblemStatTraits.hpp

amdis/functions/CMakeLists.txt

amdis/functions/GlobalBasis.hpp

docs/reference/DOFVector.md

docs/reference/GlobalBasis.md

docs/tutorials/grids-and-discretefunctions.md

test/DOFVectorTest.cpp

test/FlatPreBasisTest.cpp

test/ProblemStatTest.cpp