Offline operation and some more

[VolatileCable]

Currently, even when you have all the local files cached (contents+cetk+tmds) it won't create a WAD when you don't have internet access. (tested with cdndir)

Also for the cdn mirror usecase it would be nice to have an additional more relaxed option besides the "localuse", that just assumes all preexisting files are good and doesnt even try to verify the sha1 in the tmd, in case there's no ticket available on the NUS server. Currently it just redownloads all of them each time as it cant verify the contents when you use eg the script in Issue #1 . Or really just skip the download altogether, as afaiu there's no use to the content when you dont have the titlekey from some other source.