FindConnectedRegions: organize imports
FindConnectedRegions: refactor pointState array

It is now a helper class that takes longs for indices.

This change is still a refactoring in that it hard casts the long
indices to int always, which will still result in
NegativeArraySizeException as before when width*height*slices exceeds
2G elements. But this change paves the way for improving the behavior.
FindConnectedRegions: implement Comparable<Region>
FindConnectedRegions: add missing @Overrides
FindConnectedRegions: remove unneeded else clause
FindConnectedRegions: avoid deprecated method
FindConnectedRegions: prune unused variable
FindConnectedRegions: fix whitespace indentation
FindConnectedRegions: avoid raw type
FindConnectedRegions: make PointState handle >2GB

It now keeps an array of byte arrays internally,
to exceed Java's 2GB array limitation.
Merge pull request #1 from fiji/large-images

Large images