Fixed VideoFile closure
The video codec was retrieved twice
The FFMPEG headers directory weren't added to search paths
Added missing constructor to VideoSource
Fixed VideoSource inheritance (Transformable wasn't public)
Corrected some comments in VideoSource.hpp
Implemented the missing VideoSource destructor
Implemented VideoSource::setStatus() protected method
Implemented Video class
Fixed a header protection name conflict
Updated the video example
Implemented FPS retrieval
Implemented the frame count retrieval

I also removed the need to mention the frame count when loading a video file.
Updated the video example