Add the possibility to disable the individual warnings

I'm not happy with this, importing both `warning` and `WARN` is redundant, but I don't know how to avoid it. I'm also not sure if there is no some better way to selectively suppress and annotate the log messages, Python logging module is mind bogglingly complex and horribly documented, so I'm completely lost in it.

Please let me know if you can see how to do it better.

But at least this does seem to work...