max_msg should be dynamic

[Peter]

In order to show the history dependant on member status, I suggest to add max_msg to the list of dynamic parameters.

Same for max_privmsg and channels.

In this way we can distinguish between different groups.

[phpfreechat]

it will not work because this parameter is used to cleanup old messages.
So if you have max_msg=0 for on person and max_msg=20 for another, the first user will just delete the 20 messages.