change the `while` loop to check if the two windows created by this example still exist, stop the program otherwise

removed binary

update

fix for #6598

All of these: (performance) Prefer prefix ++/-- operators for non-primitive types.
[modules/calib3d/src/fundam.cpp:1049] -> [modules/calib3d/src/fundam.cpp:1049]: (style) Same expression on both sides of '&&'.

Allow configuration of the square size in stereo_calib.

https://github.com/Itseez/opencv/issues/6456

1. Following condition is True on each iteration becuase -1 % 0xFF is 255 not -1

code = cv2.waitKey(100) % 0x100
if code != -1:
   break

this were resetting point position on each cycle not on key press as intended

2. Previous small bug were masking serious bug with matrix operation on matrices of incorrect size.
   As the result on 2nd iteration of internal cycle program has crushed.

   I have fixed it too, matrix operation was taken from examples/cpp/kalman.cpp where it looks like
   randn( processNoise, Scalar(0), Scalar::all(sqrt(KF.processNoiseCov.at<float>(0, 0))));
   which is something totally different from previous code here.

   Example behave as it should now, i.e. point moving by circle trajectory as in C++ example.

responses must be float, else we trigger an assertion in line 150

Added some asserts.