Create terminal UI (ncurses) wrapper

[cmannett85]

As a part of #144 ncurses is being used to create the UI. As a C interface it doesn't fit the patterns used in this project very well, I'm not doing any error checking with it as it involves manually checking error codes and throwing, and using it directly means that swapping it out for another library will be painful.

The solution is to create a facade (wrapper) object for it that exposes just the functions I need, does any initialisation and cleanup as a part of its lifetime, and does all the error management.