Make EphemerisParser support fetching vector tables
Allow "CT" or "UT" for time suffixes

These stand for Universal Time and Coordinate Time. I'm not sure of
their effective meaning insofar as Tengai should be concerned, so It'd
probably be a good idea to strip them off before parsing the timestamps.

Right now they are probably just interpreted as timezones.

See http://ssd.jpl.nasa.gov/?horizons_doc#time
Merge branch 'master' of github.com:zacstewart/tengai