Fix GPU example build failed with cuda 5.5
OCL: tests: repair/disable failed tests in ocl module
OCL: tests: repair moments implementation in master branch, enable tests
Update cmake files by using CUDA_CUDA_LIBRARIES
fixed cpp wrappers of ML tree-based models
Removed old Python detection cruft.

None of this should be relevant as of CMake 2.8.7.
Bumped minimal Python version to 2.6.

Rationale: we already depend on it (e.g. some scripts use print_function).
Refactored NumPy detection.

Most importantly, added support for multiple include directores,
but also did some general cleanup.
Moved Sphinx detection outside of the PYTHONINTERP_FOUND block.

Who knows, maybe the user's Sphinx installation uses a Python we couldn't find.
Take into account SpecLad's comments
Remove useless modifications
Ignore Windows' Thumbs.db
Merge pull request #1340 from SpecLad:python-updates
Merge pull request #1327 from alalek:ocl_master_tests_fix
Merge pull request #1339 from mdim:ml_cpp_wrappers_fix
Merge pull request #1267 from clhsieh:gpu_example_build_failed_with_cuda5p5
Merge pull request #1341 from roynos:master
Merge branch 'branch_ximea'
Merge branch 'master' of https://github.com/Itseez/opencv.git