Restructure project layout to closer match Stackato hosting enviroment

Restructures the project layout as follows:

```
HOST                                      VM                       Comment
public              ->               /app/app/public           Webroot
db                  ->               /app/app/db               DB dumps, installed by bin/start.sh
Rakefile            ->               /app/app/Rakefile         build script
stackato.yml        ->               /app/app/stackato.yml     Deploy options
                                     /app/buildpack            Cloned mrdavidlaing/stackato-buildpack-wordpress 
.build              ->               /vagrant/.build           All the stuff to launch & configure the dev VM
```

Note that:

1.  Everything on the VM happens in `/app`; just like Stackato
1.  After `vagrant ssh` you should `cd /app/app` and then run your `rake` commands from there.  Any changes you make on the `HOST` will automatically get copied into `VM:/app/app` (eg, you can edit your `HOST:Rakefile` and the run it on the VM via `cd /app/app` `rake`
1.  The concepts of `src/` and `dist/` is gone.  Edit the files in `HOST:.`, and they get automatically synced into `VM:/app/app`  **
1.  `VM:/app/buildpack/compile` adds extra files (wordpress, config, runtimes) to `VM:/app/app`, but these are NOT synced back to `HOST:.`.  This keeps `HOST:.` nice and clean, so you are only editing _your_ files.
1.  All the scripts related to controlling the dev VM have moved into `HOST:.build` -> `VM:/vagrant/.build`  This prevents them cluttering up your repo, allowing you to focus on *your* code

** Hiphop-php doesn't detect file changes in a Vagrant shared folder.  To get around this we setup a Vagrant shared_folder to map `HOST:.` -> `VM:/vagrant`.  `VM:/vagrant/.build/sync_app_on_host_2_app.sh` runs in the background, **polling** for file changes in `VM:/vagrant` which it then copies to `VM:/app/app`. Note that this is **one way only**. See `HOST:.build/sync_app_on_host_2_app.log` for details of what syncing is going on.