Log Message:
Update to 2.3.1

Add a python option (off by default).

2.3.1
(August, 2011)
New Functionality and Features
* Retina module has been contributed by Alexandre Benoit (in opencv_contrib
  module).
* Planar subdivisions construction (Delaunay triangulation and Voronoi
  tesselation) have been ported to C++. See the new delaunay2.cpp sample.
* Several new Python samples have been added.
* FLANN in OpenCV has been upgraded to v1.6. Also, added Python bindings
  for FLANN.
* We now support the latest FFMPEG (0.8.x) that features multi-threaded
  decoding. Reading videos in OpenCV has never been that fast.
* Over 100 issues have been resolved since 2.3 release.

2.3
(July, 2011)
Modifications and Improvements since 2.3rc
* A few more bugs reported in the OpenCV bug tracker have been fixed.
* Documentation has been improved a lot!

2.3rc
(June, 2011)
New Functionality, Features
* Many functions and methods now take InputArray/OutputArray instead of
  "cv::Mat" references. It retains compatibility with the existing code and
  yet brings more natural support for STL vectors and potentially other
  "foreign" data structures to OpenCV.
core:
* LAPACK is not used by OpenCV anymore.
* Arithmetic operations now support mixed-type operands and arbitrary number
  of channels.
features2d:
* Completely new patent-free BRIEF and ORB feature descriptors have been
  added.
* Very fast LSH matcher for BRIEF and ORB descriptors will be added in 2.3.1.
calib3d:
* calibration.cpp sample. With the new pattern calibration accuracy is
  usually much higher.
stitching:
* opencv_stitching is a beta version of new application that makes a panorama
  out of a set of photos taken from the same point.
python:
* Now there are 2 extension modules: cv and cv2. cv2 includes wrappers for
  OpenCV 2.x functionality. opencv/samples/python2 contain a few samples
  demonstrating cv2 in use.
* Over 250 issues have been resolved.