Add more examples to CppMicroServices.

[ameya7295]

I have implemented a simple math example. This example makes it easy to understand how to add, multiply using CppMicroService. I need this to be added to CppMicroServices.

[jeffdiclemente]

@ameya7295 please feel free to create a pull request which adds this simple math example. I suggest adding it under doc/src/examples within the source tree.