performance: deactivate cherrypy autoreload - add option to allow autore...

Deactivate cherrypy autoreloader by default.  The autoreload feature uses a lot CPU cycles (20% of all CPU on Raspberry Pi) 
Systems using cherrypyserver will need to stop-restart the server if the underlying code changes (in the same way as Apache and Nginx would need a restart)
To over-ride the new behaviour, use the manage command "runcherrypyserver autoreload=True"