[PATCH] QuadBuckets for Node storage

[hansendc]

• What it affects when applied: It should have the same behavior as the existing ArrayList. I would imagine that it will be slower to iterate through than an ArrayList.

• What it improves when applied: Functionally, nothing. Immediately, it helps my changes to the UnconnectedWays in the validator run about 100x faster.

TODO:

1. handle when nodes change locations
2. expose the searching interface
3. make the QuadTiling code more generic so that it can be used for non-latitude/longitude
4. make QuadBuckets able to store objects other than Nodes, like Ways or other BBoxes

I'm happy to work on these in any order, or to work on other enhancements first.

[stoecker]

(In [2165]) applied #3532 - path by Dave Hansen - infrastructure for faster data access