- removed tr1 usage (dropped in C++17)
- moved includes of vector/map/iostream/limits into ts.hpp
- require opencv_test + anonymous namespace (added compile check)
- fixed norm() usage (must be from cvtest::norm for checks) and other conflict functions
- added missing license headers

initial commit; ml has been refactored; it compiles and the tests run well; some other modules, apps and samples do not compile; to be fixed

minor fixes in CvGBTrees, its test and sample

reworked nearly all of the OpenCV tests (except for opencv_gpu tests) - they now use the Google Test engine.

Gradient Boosting Trees (CvGBTrees) added to opencv mll. Test for all CvGBTrees public methods added.