Container, extractor module, resources on tiles.

[ADDED]     Container module: stocks extracted resources.
[UPDATED]   Distribute extracted resources among connected containers.
[MOVED]     Path finding logic extracted, generalized into PathUtils.
[ADDED]     neighbours utility in PathUtils.
[ADDED]     Resource distribution across the game map.
[ADDED]     Level types determine what resources their tiles support.
[ADDED]     Convenience methods when doing Coordinate stuff on something that knows its level.