Bad Calculator as practice with C++.

This was worked on using Visual Studio Code with C/C++ extension. Standard is C++11. Can be changed in tasks.json.

2018/11/25: Catch2 added for testing. Make sure to run task to build Catch2 before running tests to reduce compile time. New tests may fail due to precision. Need further investigation to solve the problem.

Json files are to configure the extension.

For c_cpp_properties.json, modify "compilerPath" to the path of your gcc, depending on your OS.