rewrite !config because it is very confusing

[jesopo]

this will be a big change in expected behaviour by people already familiar with !config but i think it is definitely worth it in the long run.

proposed changes:

!config c setting value !config *c setting value

!config c:#channel setting value !config #channel setting value

!config u setting value !config *u setting value

!config u:nickname setting value !config nickname setting value

!config b|s setting value !config *b|*s setting value

!config c -setting !unconfig *c setting