Update/kepler

This pull request is for (1) to update the OP2 applications with the optimizations for Kepler generation NVIDIA GPUs and (2) to address a request to handle the errors eminating from HDF5 when attempting to read op_dats that does not exist in a file. The latter is required in Hydra. 

To Handle the HDF5 errors, we now return a NULL pointer in the  C/C++ API if there was an error in reading an unknown op_dat or op_map. For the FORTRAN API the size of the op_dat is return in an integer "status" variable if successful or a negative number if unsuccesful. Under MPI, the size of the array returned is the local size held on a given MPI rank for this op_dat. Examples of both are added to airfoil's HDF5 versions