Refactor DB to initiate connections on first query

Now the DB interfaces will only load a connection if they are actually
used a first time. This also allows someone who does not have PG or
Redis installed to run hurl.
Update gems to latest versions
Serve static files via Rack

Move static file serving directly to Rack. This passes off the load of
static file resolution directly to the server.
Use ruby 2.0
Merge pull request #20 from carlosdp/revamp

Update Ruby/Gems and move static file serving to Rack