Unified handling of InputOutputArrays in Python wrapper generator

This makes arguments of type InputOutputArray required in python unless they
have a default value in C++.

As result following python functions changes signatures in non-trivial way:

* calcOpticalFlowFarneback
* calcOpticalFlowPyrLK
* calibrateCamera
* findContours
* findTransformECC
* floodFill
* kmeans
* PCACompute
* stereoCalibrate

And the following functions become return their modified inputs as a return
value:

* accumulate
* accumulateProduct
* accumulateSquare
* accumulateWeighted
* circle
* completeSymm
* cornerSubPix
* drawChessboardCorners
* drawContours
* drawDataMatrixCodes
* ellipse
* fillConvexPoly
* fillPoly
* filterSpeckles
* grabCut
* insertChannel
* line
* patchNaNs
* polylines
* randn
* randShuffle
* randu
* rectangle
* setIdentity
* updateMotionHistory
* validateDisparity
* watershed

samples/python2/calibrate.py

@@ -27,7 +27,7 @@ if __name__ == '__main__':
         img_mask = img_mask[0]
     except:
         img_mask = '../cpp/left*.jpg'
-    
+
     img_names = glob(img_mask)
     debug_dir = args.get('--debug')
     square_size = float(args.get('--square_size', 1.0))
@@ -46,7 +46,7 @@ if __name__ == '__main__':
         if img is None:
           print "Failed to load", fn
           continue
-        
+
         h, w = img.shape[:2]
         found, corners = cv2.findChessboardCorners(img, pattern_size)
         if found:
@@ -65,7 +65,7 @@ if __name__ == '__main__':
 
         print 'ok'
 
-    rms, camera_matrix, dist_coefs, rvecs, tvecs = cv2.calibrateCamera(obj_points, img_points, (w, h))
+    rms, camera_matrix, dist_coefs, rvecs, tvecs = cv2.calibrateCamera(obj_points, img_points, (w, h), None, None)
     print "RMS:", rms
     print "camera matrix:\n", camera_matrix
     print "distortion coefficients: ", dist_coefs.ravel()