Also improve and clean up command line usage output, as well as add
automatic lookup of correct workshop depot id for UGC, instead of requiring
it on command line (usually assuming app id).
Console.WriteLine("\t-app <#>\t\t\t\t- the AppID to download.");
Console.WriteLine();
Console.WriteLine("Optional Parameters:");
Console.WriteLine("\t-depot <#>\t\t\t- the DepotID to download.");
Console.WriteLine("\t-cellid <#>\t\t\t- the overridden CellID of the content server to download from.");
Console.WriteLine("\t-username <user>\t\t\t- the username of the account to login to for restricted content.");
Console.WriteLine("\t-password <pass>\t\t\t- the password of the account to login to for restricted content.");
Console.WriteLine("\t-remember-password\t\t\t- if set, remember the password for subsequent logins of this user.");
Console.WriteLine("\t-dir <installdir>\t\t\t- the directory in which to place downloaded files.");
Console.WriteLine("\t-os <os>\t\t\t- the operating system for which to download the game (windows, macos or linux, default: OS the program is currently running on)");
Console.WriteLine("\t-filelist <filename.txt>\t\t- a list of files to download (from the manifest). Can optionally use regex to download only certain files.");
Console.WriteLine("\t-depot <#>\t\t\t\t- the DepotID to download.");
Console.WriteLine("\t-manifest <id>\t\t\t- manifest id of content to download (requires -depot, default: current for branch).");
Console.WriteLine();
Console.WriteLine("\t-ugc <#>\t\t\t\t- the UGC ID to download.");
Console.WriteLine();
Console.WriteLine("\t-username <user>\t\t- the username of the account to login to for restricted content. ");
Console.WriteLine("\t-password <pass>\t\t- the password of the account to login to for restricted content.");
Console.WriteLine("\t-remember-password\t\t- if set, remember the password for subsequent logins of this user.");
Console.WriteLine();
Console.WriteLine("\t-beta <branchname>\t\t\t- download from specified branch if available (default: Public).");
Console.WriteLine("\t-betapassword <pass>\t\t- branch password if applicable.");
Console.WriteLine();
Console.WriteLine("\t-dir <installdir>\t\t- the directory in which to place downloaded files.");
Console.WriteLine("\t-all-platforms\t\t\t- downloads all platform-specific depots when -app is used.");
Console.WriteLine("\t-os <os>\t\t\t\t- the operating system for which to download the game (windows, macos or linux, default: OS the program is currently running on)");
Console.WriteLine("\t-filelist <file.txt>\t- a list of files to download (from the manifest). Can optionally use regex to download only certain files.");
Console.WriteLine("\t-validate\t\t\t\t- Include checksum verification of files already downloaded");
Console.WriteLine();
Console.WriteLine("\t-manifest-only\t\t\t- downloads a human readable manifest for any depots that would be downloaded.");
Console.WriteLine("\t-beta <branchname>\t\t\t\t- download from specified branch if available (default: Public).");
Console.WriteLine("\t-betapassword <pass>\t\t\t- branch password if applicable.");
Console.WriteLine("\t-manifest <id>\t\t\t- manifest id of content to download (requires -depot, default: current for branch).");
Console.WriteLine("\t-max-servers <#>\t\t\t- maximum number of content servers to use. (default: 8).");
Console.WriteLine("\t-max-downloads <#>\t\t\t- maximum number of chunks to download concurrently. (default: 4).");
Console.WriteLine("\t-cellid <#>\t\t\t\t- the overridden CellID of the content server to download from.");
Console.WriteLine("\t-max-servers <#>\t\t- maximum number of content servers to use. (default: 8).");
Console.WriteLine("\t-max-downloads <#>\t\t- maximum number of chunks to download concurrently. (default: 4).");