Add more useful error messages on not finding files.

Add useful error messages for errors in finding files related to the GLIMPSE /
EMAF routines.  Also, add check in distance_omnibus.pro to actually stop
running if an error occurs during one of the prob_* calls.

	modified:   create_local_files/omni_glimpse_emaf.pro
	modified:   create_local_files/omni_glimpse_starsub.pro
	modified:   distance_omnibus.pro
	modified:   emaf/omni_emaf_morph.pro
	modified:   subroutines/omni_load_ffore.pro