[C+B] Add PlayerChangedChunkEvent. Adds BUKKIT-4205

Issue:
Currently the way to track player movement(PlayerMoveEvent) gets called a lot, and is more precise than some plugins need.

PR Breakdown:
This PR, with the according Bukkit PR, adds a method to track a player's movement with less precision, which is also called less, and is less abusive on servers.

Bukkit PR:
Bukkit/Bukkit#911

JIRA Ticket:
https://bukkit.atlassian.net/browse/BUKKIT-4205