v1.2.0 scrolling can be held down and refactoring

What's Changed

• Hold-scroll-buttons by @SP4CEBARsystems in #22
• Refactor-1-clarify-and-handle-termination by @SP4CEBARsystems in #24
• Refactor 2: oop, name consistency, docstrings, and prints by @SP4CEBARsystems in #23

Full Changelog: v1.1.0...v1.2.0