integrate SGBM in block_matching.py still there are some things to clean
also added : sgbm.cpp_opencv2.4.6 (which compiles only in 2.4.6)
changed interface of stereo_hirshmuller_2002 wrapper to add path to mask as a parameter
changed interface of stereo_hirschmuller_2008/callSGM.sh to pass the output
mask as a parameter
interface change to compute_disparity_map
updated docstrings in wrapper callSGBM.sh