A slew of changes for new images/os_info tables. disk_images is gone,
replaced by the "images" table. New os_info table is added. New web pages to add and delete OSIDs to/from the os_info table, for use in the NS file. tb-create-os is gone. handle_os no longer operates on the tbcmds file, and no longer writes anything into the ir file. Moved the setting up of os state (nodes table) from os_setup to handle_os, where it should be. os_load and sched_reload now take a single argument, the name of the imageid from the images table.