Sat 2 Sep 2017 : added the cuda_set.h and cuda_set.cu, copied from Path_GPU.
  Added first version of mgs.h and mgs.cu, extended the makefile.

Fri 1 Sep 2017 : added templated version of mgs_small.cu, updated makefile.

Wed 30 Aug 2017 : added BS_QR as a parameter in mgs_large_row_reduce.cu,
  provided templated version of mgs_large_backsub.cu, updated makefile.
  Fixed underscore in the definition of the name in r_pos.cu.
  Added the function log2ceil, prototyped in log2ceil.h and defined in
  log2ceil.cpp, needed in mgs_large_row.cu, which is now templated,
  updated the makefile.  Added auxiliary get_grid.h and get_grid.cu,
  needed in mgs_large_block_reduce.cu, now templated, update makefile.
  Removed RealType from templates in mgs_large_backsub.cu.
  Modified mgs_large_block.cu so it is templated, updated makefile.

Tue 29 Aug 2017 : added the definition of the utility function r_pos.cu
  and defaults to mgs_large_norm.cu so it compiles, see the makefile.
  Added #ifndef statement to r_pos.cu to prevent multiple includes.
  Made a templated version of mgs_large_row_reduce.cu, updated makefile.

Mon 28 Aug 2017 : made a templated version of mgs_large_norm.cu
