in dev_appserver, make published fb posts only visible to the author (aka "only me")
update oauth_dropins
fix encoding error constructing tweet preview

unicode base_url could not be mixed with utf-8 str preview_content.
compare unicodes instead of strs in twitter_test
Merge pull request #13 from kylewm/base_url-encoding

fix encoding error constructing tweet preview
mention in preview_create() docstrings that return type is unicode string
create: unify order of precedence for content vs summary vs name. fixes #228