Attempt to fix dupe exception bug in CommandManager

Also added back making subcommands from other classes / already loaded commands
Revamped help System a little

There is now only one HelpNode for each command, that knows all aliases.
Saves some memory.
Also allows for grouping help context so there won't be
2 pages of help context telling the same thing for x different aliases of a command.
Help will now display a list of all known aliases instead.