FileFormat subroutines standardization and other files formatting

Trailing blanks removed, comments and formatting

GMSH:
  use iunit in defgmsh and close gmsh file
CGNS:
  mesh check moved to readcgnszone
  close removed from readcgnszone and left in importcgns_mesh
STRING:
  modify some routines and use preprocessor macros
IOCFD:
  added cfd_write
IO_UNIT:
  simplified getnew_io_unit and close_io_unit
  renamed io_unit_state to io_unit_opened
Full read fluent file with no file written

Fluent file is fully read
Vertices are stored in umesh
Faces are not stored in umesh
File is not written

fluent/importfluent_mesh.f90:
fluent/fluentread_ustmesh.f90:
  top level subroutines added
fix string bugs and add build.sh