This breaks backwards compatibility for all getWorld() methods, but
shim methods were added for binary compatibility with method calls that
use LocalWorld.
This keeps things simpler by not dealing with redundant implementations
for single change and multiple changes.
This also let regions handle related changes in a more efficient way
(for example recalculates region components only when needed).
Added some missing license blocks
Added "and contributors" to all copyright notices.
Added $Id$ to files that were still missing it.
Changed "All rights reserved" to GPLv3 on Injector.java.
