converted old haar cascades to the new format; added the conversion function; added OpenCL optimization into CascadeClassfier; optimized the data structures and CPU code for the stump case.

Conflicts:
	doc/tutorials/definitions/tocDefinitions.rst
	modules/core/include/opencv2/core/core.hpp
	modules/core/src/system.cpp
	modules/features2d/src/freak.cpp
	modules/ocl/include/opencv2/ocl/ocl.hpp
	modules/ocl/src/cl_context.cpp
	modules/ocl/test/test_api.cpp

See feature 2862