Improve error message when specified depot is not available for current platform.
Fix crash when a CDN server connection times out.
Remove special depotfromapp handling; no longer necessary.
Don't create folders for excluded files.
Specify that anonymous account will be used when no credentials are given.
Handle -user and -pass as -username and -password respectively if the latter are not present.
Merge branch 'master' of github.com:SteamRE/DepotDownloader
Remove gross hack needed for creating ChunkData objects before SteamKit 1.5.1.
Merge branch 'master' of github.com:SteamRE/DepotDownloader