deck_macroadd: <key> | up/down | <delay> :: <command>

Adds a command to the macro associated with the given key and direction.

• key is the key to add the macro to - note that this is zero-indexed
• up/down determines which direction the macro will be added to
• delay is optional; it is the delay in milliseconds of the command in the macro
• command is the command to be added to the macro - in the standard format