VIS: Warn when a user passes an ignored argument
So the plot method is quite... flexible (bloated). This does give great flexibility for quickly plotting stuff, but not all args make sense for every kind of plot. Some plots (for example PiePlot) will ignore arguments like `logx` since it doesn't make any sense. This case is obviously nonsense, so it probably won't happen, but it would be nice to decorate the `_args_adjust` methods to warn when arguments are being ignored / adjusted if the user has explicitly changed them from the defaults. I should be able to do this one.
