Support setting application_name via init_sa:
http://stackoverflow.com/a/15691283
Tighten up to only set the engine variable once.
Lost link to answer from Mike Bayer.
Simplify to use kwargs, so that other options could be passed in as well:
http://www.postgresql.org/docs/current/static/libpq-connect.html#LIBPQ-PARAMKEYWORDS
Merge pull request #4 from davidblewett/master

Support setting application_name via init_sa