F_Front: Missing support for ieee_arithmetic

[haraldkl]

The intrinsic module ieee_arithmetic is not supported.
Compiling this module:

module tem_isNaN_module
  use, intrinsic :: ieee_arithmetic, only: ieee_is_nan
end module tem_isNaN_module

results in the following message:
"mwe.f90:tem_isnan_module", line 2: failed to import module 'ieee_arithmetic'

[clementval]

@haraldkl The IEEE intrinsic modules are defined in this PR #11. You can merge it in your current master to have them.

[haraldkl]

Thanks! I'll give it a try.