WIP: More command-line stuff

* Adds "help" command which just references getCommands, so you know what you can do.
* Adds "getArgTypes" command so you can see what the arguments of a command are.
* Adds nice error handling when the arguments are wrong rather than crashing.
* Fixes an error with Wallet by, for now, not using it.
* Give a better error message when no command is used.