applied patch by Will Lucas; improved separable filter performance (in particular cv::GaussianBlur) on 16s images (for [much] faster SIFT)

e.g. "n += abs(sign(value))"  or  "n += sign(cv::norm(value) > eps_64"

fix createOpticalFlowNeedleMap

Completed findHomography test (source data has type CV_32FC2). In plans add the same checking for vector <Point2f>.

Created perf tests for cornerHarris, cornerEigenValsAndVecs, goodFeaturesToTrack, adaptiveThreshold, HoughLines.