thresholding: Add method for fetching thresholded image. Fix image setter
thresholding: Fix pix convert error. Fix mem leak. Fix name
thresholding: Add test for thresholded image fetching
thresholding: Fix image data problem. Add comments. Refactor test case
Merge pull request #99 from BamX/thresholding

Removed use of ImageThresholder from setImage. Added method for fetching a thresholded image manually. Fixes #97 and #78.