Revamped command parser

[finnbar]

This allows subcommands to actually fail properly - previously if a subcommand failed, it would default to the main command. However in cases like

.quote add "blah - author

we would much rather give an error specific to the add command, rather than defaulting to treating this as .quote run with the author add "blah - author.

As such, once we parse the name of a subcommand, there's no going back - the only parser run on the arguments is the one for that subcommand.

Fixes #106, and improves error handling somewhat.

[finnbar]

Also fixes #109 - for .sayblah, chunk was consuming the prefix say and then complaining with an unknown error when it expected spaces instead of blah.

[L0neGamer]

tested the lengthened command name thing, as well as the subcommand stuff. one thing that seems weird is that when I mangled quote add, the error message didn't pop up, instead I got unknown error. I'll investigate this now.

EDIT:
after a quick investigation, I found the error. Simply replace the left with the right in smart parser and it should be good

to use <?> the original parser must not have consumed any input, which adding try handles.

https://github.com/L0neGamer/tablebot/tree/error-on-subcommand