Implement cut and paste functionality.
The cut function should cut one line of text per invocation and place it in a clipboard buffer.
The paste function should insert the content of the clipboard at the cursor.
Also implement a copy function that works similar to the cut function, however, without deleting any content.
Implement cut and paste functionality. The cut function should cut one line of text per invocation and place it in a clipboard buffer. The paste function should insert the content of the clipboard at the cursor. Also implement a copy function that works similar to the cut function, however, without deleting any content.