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

linetype -> lineType

all video processing samples use camera as default source (and fallback to synth in case of capture error)

some old cv api use cleaning

- continuous feature detection
- track verification by reverse tracking

squares.py sample added

fixed "import cv" in the new python samples. corrected Python bindings to match the documentation and vice versa (NOTE: in cv2.stereoCalibrate the parameter ordering has been changed)