introducing a tutorial for the retina model
adding retina tutorial
updated tutorial, need spell check, validation, nicer images and a discussion on parameters
updated tutorial, rapid spell check, retina parameters discussion added
added retina code tutorial
updated first image sample
minor update
minor updates for doc redirections and tutorial images size
added compute function to Feature2D (dirty workaround for #2699)
Front/back camera constants semantic for Android fixed (Bug #2839).

Front/Back camera constants' values changed;
Additional camera facing check added for JavaCameraView.
fix installation of main module headers

see: http://code.opencv.org/issues/2897

The order of the 2 conditions is really important, as every MATCHES
operator sets ${CMAKE_MATCH_1}, which is needed inside the condition
block. Ideally, this should be done using a single regex with a
negative forward lookahead, but CMake doesn't seem to support this
Move legacy part of opencv_contrib to separate header
Drop old python interface
Drop old python samples and tests
Remove documentation for old python wrapper
Turn pyopencv_to and pyopencv_from into templates

This protects from unwanted implicit conversions between types at compile time.
Add HammingDist test case
Untabify
Pass query type T into kernel
Enable runtime type definition in kernels