Feature/increase feedback

[Aldo-f]

Perception of inactivity:

• It tells what it will do, so that we know that is not just stuck;
• Change default -v from quiet to info
• Some basic info after each file completion;

In general:

• User can specify ffmpeg setting -v; (-ffmpeg-v quiet)
• Checking more for mistakes in the fetching of data by a file instead of a URL;
• Retuning $null when streamDetails is empty;
• Consistency using ' or ";
• Updating README.md and usage command in program;
• Check if at least one file info was fetched before continuing;