Fixed reltool config, moved to apps dir

Fixed the release name in the reltool config file.

Moved cells to the apps dir and added "apps" as the lib dir so
reltool knows where to find the cells app.

Updated the cells executable to add apps/cells/src and apps/cells/ebin
to the path.

I'm still floundering around figuring out different ways ease running
the system. I don't really need a release right now (i.e. a complete
system I can copy to another machine) but it doesn't hurt and I can run
the app simply by calling rel/bin/erl. I'm thinking of escriptizing the
reltool commands so I can build a release with one command. I'd also
like to just run cells from the console; I know there's a way to get
Erlang to generate a script file where you can run something like "cells
start|stop|console|etc." so I'll have to figure that out.

Note that this reltool config (release/cells.config) requires a "rel"
directory to be created.