add CMakeLists.txt to cpp dir

src/cpp/CMakeLists.txt

+cmake_minimum_required(VERSION 3.5)
+project(BallTracking CXX)
+set(CMAKE_CXX_STANDARD 11)
+
+
+add_executable(BallTracking BallTracking.cpp)
+
+set_target_properties(BallTracking PROPERTIES LINKER_LANGUAGE CXX)
+find_package(OpenCV REQUIRED)
+
+set(INCLUDE_DIRS ${INCLUDE_DIRS} ${OpenCV_INCLUDE_DIRS})
+set(LIBS ${LIBS} ${OpenCV_LIBS})
+target_link_libraries(BallTracking ba_balltracking ${LIBS} -lblas -lopenblas)
+target_include_directories( PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+export(TARGETS BallTracking FILE BallTracking.cmake)