First big commit/checkpoint of web changes for new slothd.
- Added a bunch of functions to get time of last activity, hours idle, and staleness for nodes and experiments. - Fixed the showexp_list page to use the new idle measures, including idle view. Idle view now runs in about 1.3 seconds instead of 13. - Changed all the "show" functions for nodes and expts to show idleness. More changes will be coming, but I wanted to commit this before I install it for real.