- Use cv::AutoBuffer rather than new allocation
- Fix "assignment operator could not be generated" warning

fixed my_umat(roi).clone() test by disabling poorly aligned ROI's. Real fix of the problem will require a separate branch in UMat::copyTo().

Avoid phi exceed PI/2 to get the negative value of cos(phi).

disable "unwanted" messages

Make Otsu and Triangle algorithms mutually exclusive in cv::threshold code.
Signed-off-by: Miroslav Benes <mbenes@suse.cz>