Tweaks to sfox_remove_tone.
More work on tone removal.
Minor tweaks to sfrx.f90.
Reconfigure sfrx to call sfrx_sub.
Fix argument handling in sfoxsim.f90.
Bring sfoxsim over from superfoxtx repository.
Updates to remove_tone() routine. Currently disabled pending more tests.
fortran_charlen_t should be size_t, not int, with Clang on MacOS.