Improve first README code snippet example

[lekkas]

The first code example in the README suggests to use

var log = require('loglevel');
log.info("unreasonably simple");

Given that the default loglevel is warn (as mentioned in the README) this snippet will need some additional loglevel setup calls to actually print a message.

I guess this example could be changed to either match the default loglevel (log.warn) or include a suggested setup method (log.setDefaultLevel() maybe).

Happy to send a README PR if this is acknowledged as an actual issue

[pimterry]

Good point, thanks! Fixed by just moving everything to log.warn