remove old hard-wired URLs for cutouts

Apparently this method doesn't work any more
clean up using dictionaries, from JJ's version
need this cutout check regardless of cadc_short_cut
we will get a 404 here if the file doesn't exist, so raise exception
turn on cadc_short_cut for vofs, with full negotiation as fall back

Use the faster short cut methods for obtaining URLs to files using
a single redirect. If it fails when it comes time to follow that
URL a second call to getNodeURL will happen with the new
fullNegotiation flag set.
some extra clarification
need to loop over all PROTOCOL nodes to get full set of URLs
pep8 variable name style
Merge pull request #21 from edwardchapin/random_access

Random access