implements skill-based poisoning charge limits and weapon coating.

[EstelMatiazi]

implements #93

What this change does is add a server setting to add a new form of poisoning to the game, that if set to true will make the maximum amount of poison charges a character can have in a weapon be dependent on their skills with poisoning instead of an arbitrary fixed number based on poison level. It also changes how many charges are added to a weapon to a number based on character skill instead of going automatically to the maximum.

The aim of this is to make poisoning more enjoyable and less maintenance-heavy for users of the skill.

If the new server setting is set to false, then the default system stays in place and nothing is changed.

[mz1193]

This is a great change and the way it's done looks great. Even if some folks don't like the idea of this, the fact that it's user-configurable should make that a non-issue.