moving FunctionSpace back in small_fem: becomes functionspace

FunctionSpace/Basis.cpp

FunctionSpace/Basis.h

FunctionSpace/BasisGenerator.cpp

FunctionSpace/BasisGenerator.h

FunctionSpace/BasisHierarchical0Form.cpp

FunctionSpace/BasisHierarchical0Form.h

FunctionSpace/BasisHierarchical1Form.cpp

FunctionSpace/BasisHierarchical1Form.h

FunctionSpace/BasisLagrange.cpp

FunctionSpace/BasisLagrange.h

FunctionSpace/BasisLocal.cpp

FunctionSpace/BasisLocal.h

FunctionSpace/CMakeLists.txt

FunctionSpace/FunctionSpace.cpp

FunctionSpace/FunctionSpace.h

FunctionSpace/FunctionSpaceScalar.cpp

FunctionSpace/FunctionSpaceScalar.h

FunctionSpace/FunctionSpaceVector.cpp

FunctionSpace/FunctionSpaceVector.h

FunctionSpace/HexEdgeBasis.cpp