Introduce a capture limit option into Twincam

[ericcurtin]

Goal
Introduction of a -C option which accepts args to determine the number of frames to be captured before the application exits.
For example if we pass twincam -C100, the application will exit after 100 frames

Acceptance Criteria

A list of verification conditions, successful functional tests, or expected outcomes in order to declare this story/task successfully completed.

The application exits once the frame count value reaches the frame limit value passed by the user.
The application exits safely, this will be verified using Valgrind.