C++/CLI Wrapper for OpenCV Selective Search so you can use it in C#

The C++ source code was taken from https://www.learnopencv.com/selective-search-for-object-detection-cpp-python/ and a C++/CLI Wrapper was created following:

https://www.red-gate.com/simple-talk/dotnet/net-development/creating-ccli-wrapper/ http://pragmateek.com/using-c-from-native-c-with-the-help-of-ccli-v2/