Remove arguments of certain commands

[pauloney]

There are instances where one wants to remove the arguments of a certain (new) TeX command like

\todo{mispelled}

but that is not a part if detex right now, which only removes the command and not the arguments of the commands it previously know or that can be dealt with in a standard way.

The command above (\todo) comes from an added on package and there is no way that "detex" could have known about it, ... so there should be a way to list new command in both the command-line and on .detex file.

There are two types of standard behaviour: KILLARGS() and STRIPARGS() but all should be looked into here ...