Samples showing read of whole streams

[DarkerStar]

I added two new samples in the "input" category, both showing how to read the entire contents of an input stream into a variable in one shot.

• read-text-stream shows how to read the contents of a stream into a string. It's mainly intended for text input.
• read-binary-stream shows how to read the contents of a stream into an arbitrary container. It's mainly intended for non-text (binary) input.

[DarkerStar]

Updated PR to current repo structure and style.