FIX: Fix encoding to allow StataReader to read urls
Fix encoding so that StataReader can correctly read URLs

closes #9231

This fix is not finished - mostly using it to document the issue.  The StringIO is returning unicode while unpack expects bytes (or string on Python 2).  This simply encodes the unicode to a new StringIO object, and is very ugly.
 @jreback @jseabold Should be fixed now. I left in the url read for now simply to to verify once that it works.  I will delete this basic test once it goes green.
 One timed out, the others all passed, so it seems ready, barring other issues in the method I used.
 minor comment, I restarted the stalled job
 @jreback Looks good.  Let me know if you need me to rebase.
 @bashtage thanks!
