add cut by bounding rectangles

i mixed it with haarcascades for eyes. works almost fine, but still can
better.
add method for mass center finder

It needs tonns of testing.
Actually, i should just decide which one is better and start to work on
haarcascades for animals.
Final loader version. simple, but it works.

It's strange but looks like smart cut and simple cut give the same
results... wasted.
Merge remote-tracking branch 'origin/test_cutter'