Undead Nights - Zombie Horde Nights

All the changes from version 0.9.5 to 1.0.1

• implemented new config system with two separate config files, one config for the mod itself and one for the horde wave (issue #6)
• it's now possible to add you own mobs (via mobIds) to a wave (issue #6)
• disable reinforcements for all horde zombies
• add config option to enable/disable spawn in water / spawn on trees, improve spawn location finding
• add event to reset spawn counter if server is stopped / rework event handling