Session persistence

[yortus]

session-file-store was causing EPERM errors on Windows (see isaacs/node-graceful-fs#104).

As a result, the code was switched over to use connect-loki.

This library doesn't look well-maintained and the following issues need addressing:

• TTL doesn't work (see ttl does not work requarks/connect-loki#7) (TODO: confirm this problem in routist).
• The store is somehow keeping the node process alive even after the HTTP server is closed. session-file-store did this too and needed cleanup code to clear the reapInterval timer. Suspect LokiJS persistence adapter is keeping things alive now, because connect-loki never closes it. See LokiJS docs (find close on the page).

Need to either find another persistence solution, or address the above issues in connect-loki.