Follow possible new db_connection API: status/2

[scouten]

Watch status of https://github.com/elixir-ecto/db_connection/pull/90/files.

May need to find a way to determine if we're inside a transaction.

[scouten]

Consider using http://www.sqlite.org/c3ref/get_autocommit.html to obtain this info. (h/t @fishcakez)

[ConnorRigby]

Waiting on esqlite #49

[Rovanion]

mmzeeman/esqlite#49 has been merged.