Fix typos in previous commit.

Fix typos (syntax errors) in previous commit to omni_grs_maskspec.pro.

 	modified:   subroutines/omni_grs_maskspec.pro
Further typo fixes to "Big Island" bugfix

Further fat-finger-syndrome fixes to omni_grs_maskspec.pro, plus addition of
Check_Math() calls to both omni_grs_maskspec.pro and omni_import_velocity.pro
to silence "Floating underflow" errors.

	modified:   create_local_files/omni_import_velocity.pro
	modified:   subroutines/omni_grs_maskspec.pro
Small fixes to clear out "underflow" messages

Addition of Check_Math() calls to clear out "underflow" messages.  Also,
adjusted the prob_parallax.pro parallax array to NOT start at zero, since the
corresponding distances (1/pxarr) should not include an infinite distance.

	modified:   distance_omnibus.pro
	modified:   dpdf/prob_parallax.pro