Fix for incorrect calcOpticalFlowPyrLK result evaluation with ARM NEON

Adding of destructor and placement new constructors for classes wrapped with CV_EXPORTS_W_SIMPLE macro

The TiffDecoder keeps an open file handle.
As a consequence the file cannot be removed
before the TiffDecoder closes the file.

* example using the Canny algorithm with custom image gradient.

* Modified example to integrate new function canny with custom gradient

Replaced quiet return from MSER:detectRegion function with exeption throwing to notify user in case small image is processed

      * accumulate, accumulateSquare, accumulateProduct and accumulateWeighted

1. if a component's variation is a global minimum than it should be a local minimum
2. for the small image with invert and blur, the MSERs number should be 20