Think about filenames when downloaded

[kelle]

I would ideally like to preserve filenames as much as possible.

Filenames are being changed in order to avoid duplicates: e.g.,
spex-prism_2MASSJ10073369-4555147_20061209_LOO07A.txt
gets downloaded as
spectra_292_spex-prism_2MASSJ16150413%2B1340079_20060902_LOO07A.txt

Also, some files being saved as spectra_284_viewcontent. They are actually FITS files, but are lacking using filenames. These are probably the ones being downloaded from CUNY Academic works where the URLs look like this: http://academicworks.cuny.edu/context/hc_pubs/article/1109/type/native/viewcontent.