config: provably correct handling of config.get args

% nodeunit tests/config.js 

config.js
✔ arrange_args - name
✔ arrange_args - name, type
✔ arrange_args - name, callback
✔ arrange_args - name, callback, options
✔ arrange_args - name, options
✔ arrange_args - name, type, callback
✔ arrange_args - name, type, options
✔ arrange_args - name, type, callback, options
✔ get - name, bare
✔ get - name.ini

OK: 10 assertions (15ms)

Works a treat, except I can't figure out what logger is doing to it when it gets loaded. Except for that details, this works quite nicely.