In Python 3, version 3.3+, PyUnicode_AsUTF8() provides similar
functionality to Python 2's PyString_AsString().
In older versions of Python 3, there is no public function to provide
the same functionality. However, the "internal" _PyUnicode_AsString()
does provide that functionality, so use it to replace
PyString_AsString().
With this patch, cv2 should compile for Python 3.[0-2].
* #1538 from StevenPuttemans:bugfix_3283
* #1545 from alalek:ocl_test_fix_rng
* #1551 from alalek:cmake_install_win
* #1570 from ilya-lavrenov:ipp_warn_fix
* #1573 from alalek:perf_simple_strategy
* #1574 from alalek:svm_workaround
* #1576 from alalek:ocl_fix_cl_double
* #1577 from ilya-lavrenov:ocl_setto_opencl12
* #1578 from asmorkalov:android_fd_cp_fix
* #1579 from ilya-lavrenov:ocl_norm
* #1582 from sperrholz:ocl-arithm-additions
* #1586 from ilya-lavrenov:ocl_setto_win_fix
* #1589 from ilya-lavrenov:pr1582_fix
* #1591 from alalek:ocl_remove_cl_hpp_h
* #1592 from alalek:ocl_program_cache_update
* #1593 from ilya-lavrenov:ocl_war_on_double
* #1594 from ilya-lavrenov:ocl_perf
* #1595 from alalek:cl_code_cleanup
* #1596 from alalek:test_fix_run_py
* #1597 from alalek:ocl_fix_cleanup
* #1598 from alalek:ocl_fix_build_mac
* #1599 from ilya-lavrenov:ocl_mac_kernel_warnings
* #1601 from ilya-lavrenov:ocl_fix_tvl1_and_sparse
* #1602 from alalek:ocl_test_dump_info
* #1603 from ilya-lavrenov:ocl_disable_svm_noblas
* #1605 from alalek:ocl_fixes
* #1606 from ilya-lavrenov:ocl_imgproc
* #1607 from ilya-lavrenov:ocl_fft_cleanup
* #1608 from alalek:fix_warn_upd_haar
* #1609 from ilya-lavrenov:ocl_some_optimization
* #1610 from alalek:ocl_fix_perf_kalman
* #1612 from alalek:ocl_fix_string_info
* #1614 from ilya-lavrenov:ocl_svm_misprint
* #1616 from ilya-lavrenov:ocl_cvtColor
* #1617 from ilya-lavrenov:ocl_info
* #1622 from a0byte:2.4
* #1625 from ilya-lavrenov:to_string
Conflicts:
cmake/OpenCVConfig.cmake
cmake/OpenCVDetectPython.cmake
cmake/OpenCVGenConfig.cmake
modules/core/CMakeLists.txt
modules/nonfree/src/surf.ocl.cpp
modules/ocl/include/opencv2/ocl/ocl.hpp
modules/ocl/include/opencv2/ocl/private/util.hpp
modules/ocl/perf/main.cpp
modules/ocl/src/arithm.cpp
modules/ocl/src/cl_operations.cpp
modules/ocl/src/cl_programcache.cpp
modules/ocl/src/color.cpp
modules/ocl/src/fft.cpp
modules/ocl/src/filtering.cpp
modules/ocl/src/gemm.cpp
modules/ocl/src/haar.cpp
modules/ocl/src/imgproc.cpp
modules/ocl/src/matrix_operations.cpp
modules/ocl/src/pyrlk.cpp
modules/ocl/src/split_merge.cpp
modules/ocl/src/svm.cpp
modules/ocl/test/main.cpp
modules/ocl/test/test_fft.cpp
modules/ocl/test/test_moments.cpp
modules/ocl/test/test_objdetect.cpp
modules/ocl/test/test_optflow.cpp
modules/ocl/test/utility.hpp
modules/python/CMakeLists.txt
modules/ts/include/opencv2/ts.hpp
modules/ts/src/ts_perf.cpp
samples/android/face-detection/jni/DetectionBasedTracker_jni.cpp
