Multi object queries for simbad

I sort of stumbled on this by accident, but it turns out that if you add newlines to a SIMBAD query, it will produce a table with *all* of the objects queried.  So this just changes `Simbad.query_object` to interpret a list of strings in this way by just placing them on newlines. 

I also added some code that stores the most recent result from a SIMBAD query - this is useful for diagnosing various things, and might be valuable when a user sees what appears to be unexpected behavior.

It also stores any errors in parsing to the result table as an `errors` attribute.  Again, useful for interpreting results when multiple objects are queried.