Bug fixes, minor feature improvement


 - It now notifies the user of permission failures
 - Control signs are no longer case sensitive
 - It no longer leaves water hanging midair after a sinking, although this only effects water within the ships borders. Water that spills outside will still hang there
 - canFly has been replaced by blockedByWater, which is more descriptive of what the attribute actually does. canFly will continue to work, so it is backwards compatible
 - Torpedoes and other moveEntities: false crafts no longer release as a result of movement
 - Typed commands now actually use the Bukkit command system for better compatibility
 - Walking off a craft, then back on, then back off again will successfully release the craft
 - Trap doors will now remember whether they were on the top or bottom of the adjacent block
 - There is a new command sign: "Release". You will never guess what it does...