connectedcomponents submission

Hi,

This is a git pull request for the following issue (that has went on way too long!).  I've fixed up the Dustin's complaints... let's get this code out there!

http://code.opencv.org/issues/1236

There are _COUNTLESS_ threads on how to do connectedcomponents almost monthly submissions to the ML.  Stackoverflow alone must have 20+ threads on this.  Most end up using cvblobslib which is often broken and too slow to boot.  There are some other implementations too and it's possible to do it opencv with findContours but it's really a bad situation atm.  People actually are rolling their own implementations still (naively).

Anyway this presents an easy to use single function call which gives the labeled image and optionally the statistics one often wants with connected components (bounding box, centroid, area) and does so with better worst case and average case performance than all the other implementations.

I hope I'll have better luck at submission than through the issue tracker.