Bukkit/Bukkit — pull request #572 by ST-DDT (2012-03-27 17:07:49+00:00)
Title: Changed PluginLoader Plugin disabling

Plugin deactivation changed: So that first the plugin A is disabled,
then all the plugins with depend A are disabled and unloaded, and after that the plugin itself will be unloaded.
This solves the problem in dependent plugins, that in onDisable needed classes from plugin A are already unloaded.