Common fixes:
- print function
- int / float division
- map, zip iterators in py3 but lists in py2

Known bugs with opencv 3.0.0
- digits.py, called via digits_video.py: https://github.com/Itseez/opencv/issues/4969
- gaussian_mix.py: https://github.com/Itseez/opencv/pull/4232
- video_v4l2.py: https://github.com/Itseez/opencv/pull/5474

Not working:
- letter_recog.py due to changed ml_StatModel.train() signature

otherwise model is only ever trained with default
parameters, and digits_adjust does nothing (for example)

Also, removed the one from modules/python/src2/cv.py and cleared its
executable bit, since it's not a script.

small fix in find_obj.py

line breaks in fitline.py description

digits.py now saves the resulting SVM classifier for use in digits_video.py

added deskew for SVN and KNearest recognition sample