Supply caching function for use as a cron job

[melinath]

Some caching functions are time-intensive, such as the noaa weather reports. Being able to set some (or all) pipettes to cache with a cron job instead of with uses would prevent occasional long loads (which with heavy traffic could affect a number of users.) Note that this would require not using memcached(?)

[harrislapiroff]

Are the management commands sufficient for this?