Allow the api to override default commands

[PainDeMie64]

Example: I want to make a command loads inputs from a file, until/from a certain time which is passed in the command. Such as: load example.txt until 15.64 or load example.txt from 2.46 And still keep the default load example.txt available to use. That could be done by overriding the command and thus making it how we want to. That would make it easier to add useful parameters instead of making additional commands for every single one.