isPath() validation test now checks for files AND directories, not just files
Add hasData() check
Add code to set ID in ResourceItem when retrieving from the cache; also, add Cache::clearAll()
Update demo; works now...
Only ignore the 'cache' and 'www/data' directories
Fix caching on ResourceLists; now it is disabled by default because ResourceItems couldn't notify parent ResourceLists of changes
Add congratulatory comments...