amplement weidhting according to L. Bourdev and J. Brandt paper "Robust Object Detection Via Soft Cascade"

    - use random from tr1 extension
    - extend cv::Boost

Added test checking that all valid fourcc values are converted properly

changed default parameters of SURF, which improved its performance. Restored bi-linear interpolation in SURF descriptor extractor. Added test for SURF homography + check for non-zero (positive) responses.