Added parallel version of detect_keypoints in C++, and bindings to it in Python.
Merge branch 'hesaff_setuptools' of https://github.com/Erotemic/hesaff into hesaff_setuptools
Fixes to the parallel version of detect_keypoints. Confirmed that it gives the same output as the original, non-parallel version (via test_pyhesaff_simple.py).
merged parallelized pyhesaff