Updated field input/output to add provenance data.

CMakeLists.txt

cmake/GetGitRevisionDescription.cmake

cmake/GetGitRevisionDescription.cmake.in

cmake/NektarCommon.cmake

library/LibUtilities/BasicUtils/FieldIO.cpp

library/LibUtilities/BasicUtils/FieldIO.h

library/SolverUtils/EquationSystem.cpp

library/SolverUtils/UnsteadySystem.cpp

solvers/CardiacEPSolver/CellModels/CellModel.cpp

...IncNavierStokesSolver/EquationSystems/IncNavierStokes.cpp