not all paths are created equal, and remove background saving
not all paths are created equal, and remove background saving

some are directories! now we're super extra duper explicit about the
URLs we create and whether or not they're directories. also re-added
assertions to prevent these errors from slipping past our defenses in
teh future.

went ahead and added similar error handling to reading the schema file
(where file not found errors are allowed).

wikimedia/apps-ios-wikipedia,wikimedia/wikipedia-ios,wikimedia/apps-ios-wikipedia,wikimedia/apps-ios-wikipedia,montehurd/apps-ios-wikipedia,wikimedia/wikipedia-ios,wikimedia/apps-ios-wikipedia,bgerstle/wikipedia-ios,montehurd/apps-ios-wikipedia,anirudh24seven/wikipedia-ios,montehurd/apps-ios-wikipedia,wikimedia/wikipedia-ios,wikimedia/apps-ios-wikipedia,josve05a/wikipedia-ios,bgerstle/wikipedia-ios,josve05a/wikipedia-ios,montehurd/apps-ios-wikipedia,montehurd/apps-ios-wikipedia,anirudh24seven/wikipedia-ios,josve05a/wikipedia-ios,bgerstle/wikipedia-ios,josve05a/wikipedia-ios,montehurd/apps-ios-wikipedia,anirudh24seven/wikipedia-ios,bgerstle/wikipedia-ios,wikimedia/wikipedia-ios,julienbodet/wikipedia-ios,wikimedia/apps-ios-wikipedia,anirudh24seven/wikipedia-ios,julienbodet/wikipedia-ios,josve05a/wikipedia-ios,julienbodet/wikipedia-ios,wikimedia/wikipedia-ios,wikimedia/wikipedia-ios,julienbodet/wikipedia-ios,bgerstle/wikipedia-ios,anirudh24seven/wikipedia-ios,julienbodet/wikipedia-ios,anirudh24seven/wikipedia-ios,julienbodet/wikipedia-ios,anirudh24seven/wikipedia-ios,bgerstle/wikipedia-ios,bgerstle/wikipedia-ios,montehurd/apps-ios-wikipedia,anirudh24seven/wikipedia-ios,montehurd/apps-ios-wikipedia,josve05a/wikipedia-ios,julienbodet/wikipedia-ios,bgerstle/wikipedia-ios,josve05a/wikipedia-ios,wikimedia/apps-ios-wikipedia,josve05a/wikipedia-ios,wikimedia/apps-ios-wikipedia,julienbodet/wikipedia-ios,wikimedia/wikipedia-ios