Merge pull request #38 from nsaje/master

Fixed cell array of Point2f/3f as input parameter
missing weights argument in detect function
fix padding option key in computeGradient method
expose computeGradient in MATLAB class as hidden function
add a new function readALTModel from opencv
expose a SvmDetector property that returns linear SVM coefficients
documentation edits
add functions to get/set FeatureDetector algorithms parameters
get name of FeatureDetector algorithm
fix markdown in docs
expose Mask option of FeatureDetector::detect
Resolved explicit pointer type
Added a keypoints output to DescriptorExtractor