Reduce logging of autoreload script

The auto-reload script (which reloads the site whenever a web file is changed) logs quite a number of messages to the JavaScript console. For example:

Hippo auto-reload connecting...
Hippo auto-reload connected 

That's annoying during frontend development, which typically involves reading messages in the JavaScript console. The auto-reload script should either not log these messages, or only at 'debug' level so they can easily be ignored/suppressed in the JavaScript console.