Movecraft

A few bug fixes for Siege, underwater explosions not working in 1.9, and a major (but rare) crash when a ship is destroyed while moving.

Also added the Assault system: basically it allows you to attack a region, damage it, and the owner has to pay to have it repaired. It is optional, settings are in the config.yml To get an idea how the config works, rename your existing config.yml run the server, then look at the config.yml it autogenerates.

Also added Cannon and AA directors. This is the ability for players on a ship to "steer" TNT and fireball projectiles in order to aim at enemy ships.