Epic : Refactor the C++ client

Overview

This issue will try to address the concerns raised as a part of issues 523, 380, 396, 438 on Kanboard.

In general, each of these topics will have a new sub-task raised to fix bugs, or add features.

Requirements

• To reduce C++ client foot print, update it to the latest possible standard keeping compatibility in mind.
• To make sure that C++ client can cross compiler
• To make sure that the C++ client can be made more efficient.
• To make sure that the C++ client code adheres to a style guide as specified here