Use find_program() to set CMAKE_C_COMPILER and CMAKE_CXX_COMPILER.

Originally the variables was set to compiler name, without absolute path.
CMake 3.0 tries to find them in CMAKE_FIND_ROOT_PATH (since 
CMAKE_FIND_ROOT_PATH_MODE_PROGRAM was set to ONLY) and fails.

Signed-off-by: Yan Wang <yan.wang@linux.intel.com>

ported from c105b729

fixes for latest changes in opencv3.0 api

waitKey() normalization

fixed mser bindings

TBBUTTONINFO struct and BTNS_xxx symbols used in the code need _WIN32_IE to be defined with at least 0x0500 value (_WIN32_IE_IE50) in order to be included from commctrl.h.