Modified chat applicatino to use in memory DB

Same as the applicatin that uses lio-fs, this does not allow for
concurrent modification of a single "DB entry", though this is
actually much easier to modify than the lio-fs based one.

See dc3601b553a2603876534ebb5deb2a4a3819197f
port to 0.8 of simple
minor
lio-simple helper
memblog no fs
memblog that stores to DB to fs (dumb version)