Static and route directory needs to be relative to the App instance

[lllama]

At the moment, the app will try and load the static and route directories from where the app is invoked, which is not what we want.

Also affects the new-route command which will create the new route in the wrong directory (relative to where the command is run, not where the app is). This might be harder to fix, however, as there's no real way to know where the app lives.